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Arthur Woo
02-10-2014, 07:15 AM
Hi all,

As I'm preparing for the upgrade, I'm wondering about the exposure and ISO settings. I'm not sure how many of you in your early days of shooting Red have experienced shooting lower ISOs (320) in daylight and not being able to bring back much, if any, of the highlights if they were overexposed (the dreaded magenta cast in the highlights), vs 800 where there's a bit more latitude to bring back a little more. It's just got me thinking about how I am going to adjust if I'm staying at the native 2000 ISO.

So my question is, are you Dragon users leaving your ISO at 2000, and just using ND/higher f-stops, or are you lowering the ISO, with the possibility of less recoverable highlights? I'm speaking mostly for outdoor daylight shots. Thanks!!

Mark L. Pederson
02-10-2014, 07:33 AM
So my question is, are you Dragon users leaving your ISO at 2000, and just using ND/higher f-stops, or are you lowering the ISO, with the possibility of less recoverable highlights? I'm speaking mostly for outdoor daylight shots. Thanks!!

You should lower the ISO to allow more light into the sensor. More light = cleaner image. I like 640-800 as a "base" ISO on Dragon for interiors, etc. - 1280 for night ext. - 320 for bright daylight - really depends on what you are trying to do. Shooting 320 on Dragon is TOTALLY different than shooting 320 on MX.

Arthur Woo
02-10-2014, 07:37 AM
You should lower the ISO to allow more light into the sensor. More light = cleaner image. I like 640-800 as a "base" ISO on Dragon for interiors, etc. - 1280 for night ext. - 320 for bright daylight - really depends on what you are trying to do. Shooting 320 on Dragon is TOTALLY different than shooting 320 on MX.

Thanks! I do editorial/doc work every now and then so I don't always have time to ensure every setting is exact from shot to shot, but it sounds like it's not as big of an issue with the new sensor

Mark L. Pederson
02-10-2014, 07:44 AM
Thanks! I do editorial/doc work every now and then so I don't always have time to ensure every setting is exact from shot to shot, but it sounds like it's not as big of an issue with the new sensor

You have a lot more room to play for sure.

David Battistella
02-10-2014, 09:05 AM
From Evan's test's here.

reduser link (http://www.reduser.net/forum/showthread.php?112105-Just-in-case-you-were-wondering-how-accurate-ISO-800-is-on-Dragon)

It appears at 800 ISO the dragon matches metered light. This is nice to know in the sense that if you RATE at 800 ISO and STAY at 800 ISO then you will get very consistent results. I've always left the MX at 320ISO and 5000 kelvin (simulating RAW) , shot charts in different lighting setups and then white balanced and try to leave things at 320 in post to keep the noise down. There are situations I have rated at 800ISO and then if I want to reduce the noise bring that down to 640 or 500 in post. IT all depends. seems like we can be a bit looser in our selections now with Dragon.

When I get my hands on one, I'll do some of my own testing.

What seems to be happening with Dragon is much more accurate sensor/iso reading when it comes to metered light.

That does not mean you are going to throw away all of the great exposure tools built into the RED OS, but it nice to location scout with a meter and then not have any surprises.

Battistella

David Battistella
02-10-2014, 10:19 AM
You should lower the ISO to allow more light into the sensor. More light = cleaner image.

This is true, more light = cleaner image, but when capturing with RED the ISO has no bearing. The only way to allow more light onto the sensor is:

1. Add more lighting
2. Open the iris or use faster lenses.

Lowering the ISO does not allow more light to hit the sensor. Lowering the ISO and opening up the aperture/removing ND, etc does.

Gunleik Groven
02-10-2014, 10:21 AM
This is true, but when capturing with RED the ISO has no bearing. The only way to allow more light onto the sensor is:

1. Add more lighting
2. Open the iris or use faster lenses.

Lowering the ISO does not allow more light to hit the sensor. Lowering the ISO and opening up the aperture/removing ND, etc does.

WHich of course is fully true.
Lowering ISO darkens the image, and most photofraphers gut-reaction to that, is to open up, though... :)

Like most DOP reacts to other metadata changes...

David Battistella
02-10-2014, 10:25 AM
Yes, of course and I know mark knows that.

But UNLIKE Alexa, the ISO is meta data is non destructive, this is not true for the ALEXA, where the ISO is baked in (unless you shoot 2K ARRIRAW) in which case we could start talking about the all advantages and brilliance of REDCODE. (now 6K RAW and much more compact) :)

So, it's just important to distinguish for clarity.

Battistella

Mark L. Pederson
02-10-2014, 10:46 AM
Yes, of course and I know mark knows that.

But UNLIKE Alexa, the ISO is meta data is non destructive, this is not true for the ALEXA, where the ISO is baked in (unless you shoot 2K ARRIRAW) in which case we could start talking about the all advantages and brilliance of REDCODE. (now 6K RAW and much more compact) :)

So, it's just important to distinguish for clarity.

Battistella

Sure - but I was responding to the posters specific question - "are you Dragon users leaving your ISO at 2000, and just using ND/higher f-stops" - which - UNLESS you are trying to get a shallow depth of field and shoot more wide open as a CREATIVE choice or go for more noise as a creative choice - would NOT be the best way to expose.

the thing about ISO being "only meta data" is a topic I spend a good deal of time talking about in Reducation - because, like Gunleik said - most DPs will react to meta-settings - destructive or not - so what I always try to drive home is -

ISO (on RED) doesn't matter EXCEPT:

#1: It effects your monitor path. And like it or not, not matter what you tell people - they will react to the monitor. Period. It is not the dumbest thing in the world to have your on set monitors dialed down a bit. Encourage those monitor luv'n folks to open up a bit.

#2: Choice of ISO may, or may not be, critical to DPs process for choosing exposure - which is rather important. So ... to say ISO is "not important" just because you can "change it later" - is a very flawed comment IMO - and I hear it often. Mostly from people who have ever used a light meter :)

David Battistella
02-10-2014, 11:08 AM
Totally get this reasoning. i'm not suggesting it's "not important", I think it is really important for people (DP's) to understand this stuff.

It's true that ISO is really a monitoring path. My point is not that it is not important, but that when it comes to exposure choices, its the shutter, aperture and filtration that matter the most (all of the things in the optical path). Is there leway later because ISO is meta data? Sure. Is that the best way to go about things? of course not.

Maybe the bigger point is that it seems that with Dragon, DP's with make a couple of ISO decisions (based on situations) and things will run more like it did with film, where you have a fixed ISO film stock in the camera. The nice part is that the system is so much more flexible now and people will rate at 1600 or 2000 if that is what they are going for.

Battistella



Sure - but I was responding to the posters specific question - "are you Dragon users leaving your ISO at 2000, and just using ND/higher f-stops" - which - UNLESS you are trying to get a shallow depth of field and shoot more wide open as a CREATIVE choice or go for more noise as a creative choice - would NOT be the best way to expose.

the thing about ISO being "only meta data" is a topic I spend a good deal of time talking about in Reducation - because, like Gunleik said - most DPs will react to meta-settings - destructive or not - so what I always try to drive home is -

ISO (on RED) doesn't matter EXCEPT:

#1: It effects your monitor path. And like it or not, not matter what you tell people - they will react to the monitor. Period. It is not the dumbest thing in the world to have your on set monitors dialed down a bit. Encourage those monitor luv'n folks to open up a bit.

#2: Choice of ISO may, or may not be, critical to DPs process for choosing exposure - which is rather important. So ... to say ISO is "not important" just because you can "change it later" - is a very flawed comment IMO - and I hear it often. Mostly from people who have ever used a light meter :)

Eric Haase
02-10-2014, 11:42 AM
Rating MX at 320 really compromises the range in highlights as the majority of the range will be under key. If your scene has a lot of values that you intend to place under key then that's great. But typically in sunny day exteriors this is not the case. You often have and want values over key so rating 800 more evenly distributes highlights and shadows. Still, at 800 on MX you have more stops under key than over. ISO in Dragon works the same way but you have more range overall with the sensor. By most accounts 1.5 stops over key and 2 under.

But the same logic applies. If you rate low on Dragon you'll have less range over key than if you rate high. Might not be as critical since with Dragon you have more range in highlights and overall range as well. But do know that by rating at 320 you are shifting where on the dynamic range you place key exposure and compromising how many stops over key exposure can be handled.

Evaluate your scene and decide where you want to place the values and then make an educated decision on which ISO to use to accommodate all the values in the scene, keeping in mind your acceptable levels for noise and how much you want to push the image in post. Testing the sensor and plotting the DR at various ISOs will show you where values fall above and below key at each ISO and how much range above and below key you have at each ISO.

Doug Beatty
02-10-2014, 12:31 PM
If there were a way to sacrifice dynamic range for light sensitivity in camera (basically a reverse HDRx) it would silence a lot of the low light performance haters. Imagine having the ability to switch from dynamic mode to night mode and pick up an extra 3 stops in the shadows- it would be like having a better C500 built into Dragon!

A lot of what I see from Dragon is that ISO 2000 at 6K scales down favorably up against MX 5K @ ISO 800. If I were to crop a 6K Dragon file properly exposed at ISO 2000 to 5K and compare it to MX 5K properly exposed at 800, I'm not so sure that Dragon would look as clean or cleaner.

I realize that the color science isn't dialed in yet, but this is what worries me about Scarlet Dragon. Yes, we get more dynamic range, but at the cost of low light performance. So, those betting on Scarlet Dragon vs. Epic MX upgrades may have backed the wrong horse if they were hoping for improved low light performance in addition to increased dynamic range.

There are quite a few tests but nobody has posted a 5K Dragon vs. 5K MX test yet, and I'd love to taste that proof pudding.

Elsie N
02-10-2014, 01:09 PM
Rating MX at 320 really compromises the range in highlights as the majority of the range will be under key. If your scene has a lot of values that you intend to place under key then that's great. But typically in sunny day exteriors this is not the case. You often have and want values over key so rating 800 more evenly distributes highlights and shadows. Still, at 800 on MX you have more stops under key than over. ISO in Dragon works the same way but you have more range overall with the sensor. By most accounts 1.5 stops over key and 2 under.

But the same logic applies. If you rate low on Dragon you'll have less range over key than if you rate high. Might not be as critical since with Dragon you have more range in highlights and overall range as well. But do know that by rating at 320 you are shifting where on the dynamic range you place key exposure and compromising how many stops over key exposure can be handled.

Evaluate your scene and decide where you want to place the values and then make an educated decision on which ISO to use to accommodate all the values in the scene, keeping in mind your acceptable levels for noise and how much you want to push the image in post. Testing the sensor and plotting the DR at various ISOs will show you where values fall above and below key at each ISO and how much range above and below key you have at each ISO.

My intentions have been to shoot the default Dragon ISO 800 (default on current build 5.1.35) for every situation... the KISS method. But the last paragraph in your post resonates... so I will copy and paste into my notes.

Thanks Eric.

Evin Grant
02-10-2014, 01:13 PM
I guess I'm just going to have to keep repeating this...

C300/500/F55 etc. have on board noise rediction that kills detail!
The Dragon is cleaner in it's RAW path and resolves more detail at higher EIs.
The noise character is also considerably more granular/organic.
All of this means truly beautiful 4000-6400 EI footage when exposed properly and processed full debayer and treated to a proper post noise reduction treatment. I will try to post an example tonight.

Evin Grant
02-10-2014, 01:17 PM
To the OP I like EI 500 for day exterior if it's standard contrast range and 1000 for backlit or high contrast scenes where I need to see more into shadows but hold highlights.

Eric Haase
02-10-2014, 01:42 PM
To the OP I like EI 500 for day exterior if it's standard contrast range and 1000 for backlit or high contrast scenes where I need to see more into shadows but hold highlights.

This is what I'm talking about! Would I shoot a moody, wintery overcast day exterior scene at 800? Probably not. Would I shoot backlit or crosslit sunny shots with white buildings being hit by the sun at 320? Probably not. Tailor the ISO to the values in the scene if you can. Sure, sometimes you may be forced to shoot a dark looking night exterior at 1000 but if a lot of the values are below key and you can shoot at 400 you'll probably achieve better results. Having said this, I've shot a lot of 800 and 1000 ISO night exteriors and taken through a DI and projected in theaters and it looks super clean. For some reason, large projection looks cleaner that looking at it on a large computer monitor. But still 800 and 1000 even with tungsten look totally acceptable. Certainly less noisy than Vision3 500T.

David Battistella
02-10-2014, 02:46 PM
Just for clarity.

i use aperture and shutter to control these things rather than the ISO setting. If I'm in a hard backlit or sunny situation like you describe, I close the iris 1 1/2 half stops and then I'm essentially rating at at ISO 800. This is where I just use the histogram over moving the ISO around. I just like to leave the ISO at 320 and only move it to 800 as a way to see more of the image. ISO 800 gives you highlight protection because you'll tend to stop down.

of course there are many factors, DOF, etc, as to why you might use ND over aperture, but I use my epic like a 320 daylight stock and expose according to whatever situation. If I set it to 800 and close down, I'm essentially doing the same thing. But I one light everything, so sometimes I choose 800 in post if the situation calls for it.

In the dragon r3ds everything is more elastic, so more freedom without penalty (hard clipping)

Battistella

Eric Haase
02-10-2014, 02:58 PM
Just for clarity.

i use aperture and shutter to control these things rather than the ISO setting. If I'm in a hard backlit or sunny situation like you describe, I close the iris 1 1/2 half stops and then I'm essentially rating at at ISO 800. This is where I just use the histogram over moving the ISO around. I just like to leave the ISO at 320 and only move it to 800 as a way to see more of the image. ISO 800 gives you highlight protection because you'll tend to stop down.

of course there are many factors, DOF, etc, as to why you might use ND over aperture, but I use my epic like a 320 daylight stock and expose according to whatever situation. If I set it to 800 and close down, I'm essentially doing the same thing. But I one light everything, so sometimes I choose 800 in post if the situation calls for it.

In the dragon r3ds everything is more elastic, so more freedom without penalty (hard clipping)

Battistella

Yeah I get it, just seems a hard way to work as things will look dark on monitors. I'd get too many squawks from village if I didn't adjust the ISO to give a full image, or something close to looking properly exposed with then intended look.

David Battistella
02-10-2014, 03:00 PM
Yeah I get it, just seems a hard way to work as things will look dark on monitors. I'd get too many squawks from village if I didn't adjust the ISO to give a full image, or something close to looking properly exposed with then intended look.

Totally agree. In those situations it's always at 800 for the monitoring path, lots of things to balance. On my own, I leave it alone. :)

battistella

Björn Benckert
02-10-2014, 03:31 PM
I like to see iso as nothing else than a slider for color grading and a way to quickly preview how the picture looks darkened or brightened in camera. The exposure will be what it is no matter what and ISO has nothing to do with it.

Zeb B
02-10-2014, 03:32 PM
Awesome thread! Suggests that there will be mucho testing when my Dragon lands with new spiffy OLPF

Mark L. Pederson
02-10-2014, 05:04 PM
The exposure will be what it is no matter what and ISO has nothing to do with it.

Unless of course, you are using an ISO rating as a method of determining aperture setting :)

It all comes down to what method you choose for determining exposure - and while the ISO does not effect the actual exposure - 9 times out of 10 - it effects how the exposure is CHOSEN.

Certainly if you are looking at the histogram - which is downstream from IRE processing and will of course change if you change the ISO.

Timur Civan
02-10-2014, 05:06 PM
Don't be afraid of ISO250......

Arthur Woo
02-10-2014, 07:14 PM
I realize that the color science isn't dialed in yet, but this is what worries me about Scarlet Dragon. Yes, we get more dynamic range, but at the cost of low light performance. So, those betting on Scarlet Dragon vs. Epic MX upgrades may have backed the wrong horse if they were hoping for improved low light performance in addition to increased dynamic range.



Where did you hear/read about this? I was under the impression that the Dragon sensor has improved low light performance

Medavoym
02-11-2014, 05:21 AM
Don't be afraid of ISO250......

Hi Timur, can you elaborate?

Especially in light of this:




But the same logic applies. If you rate low on Dragon you'll have less range over key than if you rate high. Might not be as critical since with Dragon you have more range in highlights and overall range as well. But do know that by rating at 320 you are shifting where on the dynamic range you place key exposure and compromising how many stops over key exposure can be handled.



Are you saying the range is so good with Dragon that there is absolutely no more compromise anymore?

David Battistella
02-11-2014, 06:01 AM
It's been widely stated that there is less ISO penalty with dragon does not exist the way it does in epic MX.

It all depends on your noise tolerance level.

battistella

Eric Haase
02-11-2014, 08:09 AM
Are you saying the range is so good with Dragon that there is absolutely no more compromise anymore?

For many (if not most) scenes, yes. Very frequently the values in the scene will fall within or well below the total DR capability of the sensor, and when it does, there is no penalty for holding shadow or highlight information when you adjust the ISO. The ISO adjustment then becomes more about the noise/look you are going for.

Adam W Watson
02-11-2014, 11:37 AM
You should lower the ISO to allow more light into the sensor. More light = cleaner image. I like 640-800 as a "base" ISO on Dragon for interiors, etc. - 1280 for night ext. - 320 for bright daylight - really depends on what you are trying to do. Shooting 320 on Dragon is TOTALLY different than shooting 320 on MX.

Seconding this, I would stick to 640-800 whenever possible based on my tests. Sure you can denoise higher ISO stuff but you can do that with any camera, doesn't make it a native feature. 640-800 ISO is best.

Hrvoje Simic
02-11-2014, 12:40 PM
It should be added that raising ISO not only brings noise but also reduces color quality. Noise can be removed to an extent and organic looking noise is less distacting and may not even need removal, but poorer color rendition and reduced grading finesse is less solvable.

Robert Ruffo New
02-11-2014, 07:40 PM
Sure - but I was responding to the posters specific question - "are you Dragon users leaving your ISO at 2000, and just using ND/higher f-stops" - which - UNLESS you are trying to get a shallow depth of field and shoot more wide open as a CREATIVE choice or go for more noise as a creative choice - would NOT be the best way to expose.

the thing about ISO being "only meta data" is a topic I spend a good deal of time talking about in Reducation - because, like Gunleik said - most DPs will react to meta-settings - destructive or not - so what I always try to drive home is -

ISO (on RED) doesn't matter EXCEPT:

#1: It effects your monitor path. And like it or not, not matter what you tell people - they will react to the monitor. Period. It is not the dumbest thing in the world to have your on set monitors dialed down a bit. Encourage those monitor luv'n folks to open up a bit.

#2: Choice of ISO may, or may not be, critical to DPs process for choosing exposure - which is rather important. So ... to say ISO is "not important" just because you can "change it later" - is a very flawed comment IMO - and I hear it often. Mostly from people who have ever used a light meter :)

Cheers to your post. I could not agree more. You can't light around a shifting goal - you pick an ISO, you light around that.

Timur Civan
02-11-2014, 10:08 PM
Hi Timur, can you elaborate?

Especially in light of this:



Are you saying the range is so good with Dragon that there is absolutely no more compromise anymore?

Pretty much. Shot under a open beam 12K fresnel with no clipped highlights at 250. Looked awesome.

Patrick Tresch
02-11-2014, 10:21 PM
Don't be afraid of ISO250......

Don't be afraid of ISO1600 on Dragon. ;-)


I'll definitly shoot between 800 (MX 400) and 2000 (MX 1000) choosing 1600 as my standard.
Low light and highlight handling on Dragon got really improoved.
A small curve and a slight denoise will bring the clean and crispy image to the top.
Remember it's not a Negative. There is no joy after clipping.

Pat

Phil Holland
02-11-2014, 11:10 PM
Mark's post is pretty dead on.

I'd like to add to this conversation just a bit.

Since with REDCODE Raw ISO is a metadata and user adjustable in post doesn't mean that's the best way to work. To maintain consistency shooters should expose with a consistent method and also get familiar with the recommended usable ISO range of Dragon.

A few quick thoughts.


Usable Range.
As several people have pointed out Dragon is happy to shoot ISO 250-2000. This is what Red publishes as "fit for theatres or publication". I agree with that and this range is the basis of success when attempting to shoot "clean". You can indeed explore outside of that range however.


Texture and Tonal Consistency.
On larger projects and/or for picky folks you may want to have a consistent visual language. This is more or less something I've observed from people working with Red cameras over the years as well as my own methods for shooting. For instance, we see productions commonly shooting, lighting, and exposing for ISO 800 entirely.

This provides three things. One, a consistent noise profile overall. Two, consistent tonal placement and color response. Three, in this case since ISO 800 approximately an "mid ground" workable ISO value it gives you a good amount of flexibility in post in regards to manipulating the usable latitude. Anything really in the ISO 500-800 range provides this type of creative freedom.

That said, you main enjoy the personality of the texture of ISO 3200 and there's really nothing stopping you from rating your midtones (or whatever you are exposing to) based on that if you are attempting to achieve a particular aesthetic. If you want to shoot super clean, ISO 250 is what you are looking for.

This is more or less in practice advice and theory. If you've got big project with lots of different lighting conditions you may want to go "hog wild" with your ISO and texture choices. Just depends.


Exposing
More or less to maintain a consistent method most expose and base their ISO selections relative to midtones or 18% Gray, which is also reflected in the common use of Light Meters. However, the camera has on board tools that everybody should get very familiar with. It's very easy to use the tools on camera (Exposure Check and Video Check) to quickly make sure you are getting exactly what you want. It's important to always keep an eye on histogram levels, the Crush and Clip Bars left and right of the Histogram, and the exposure Stop Lights.

The Stop Lights inform you if you are clipping in Red, Green, or Blue - which can help you problem solve if you are.

The Crush Bar that will fill up on the left side of the Histogram informs you if you are dipping into the Noise Floor and possibly underexposing. Dipping into the Noise Floor is only really a negative if you are attempting to lift those underexposed values as it can reveal unwanted noise. However, for example if your goal is a low key shot and you know you want a crushed black in frame and you know you won't attempt lifting the values later it's okay to crush.

The Clip Bar that fills up on the right side of the Histogram is letting you know how close you are to purely clipping and blowing out a highlight. In the past (Mysterium-X) this was something to be very, very mindful of. However, Dragon has a different blown highlight "look" and overexposure roll-off which isn't contaminated with a color.

David Battistella
02-11-2014, 11:15 PM
Phil,

I have two teeny questions.

How much has RAW view changed with dragon? What rc3/rg3 ISO combo best matches the dragon RAW view?

battistella

Gunleik Groven
02-11-2014, 11:29 PM
Phil,

I have two teeny questions.

How much has RAW view changed with dragon? What rc3/rg3 ISO combo best matches the dragon RAW view?

battistella

Not sure if I see the relevance of this, but on my camera RAW view seems to have been calibrated at 320. The WB does not match at all, seems to be a quite heavy tint-correction in RG3 vs "RAW" view. (Just fired up the cam to check...)

I think that it is a very good idea to learn how the camera responds with one ISO setting, as that allows you to take image-cues from the "corrected" image as to what will work and not, and how it will work.

Yup, yu can expose for ISO 250-2000 (maybe, depending on how you do it), but if you light for those two scenarios, the edit can look pretty weird.

:)

Will Keir
02-11-2014, 11:29 PM
Mark.

Catch me if I'm crazy but changing the ISO doesn't change the amount of light that hits the sensor one bit. This is all metadata of course, no physical changes that change the amount of light entering the camera like aperture, shutter speeds or NDs of course.

Maybe there is something your saying that I'm not understanding here? There is much I don't understand, this one I'm fairly sure I have correct as other users and I have gone over it several times. Gunleik would be a good man to come in here, he's been notified and might jump on this thread to add a little clarity.


You should lower the ISO to allow more light into the sensor. More light = cleaner image. I like 640-800 as a "base" ISO on Dragon for interiors, etc. - 1280 for night ext. - 320 for bright daylight - really depends on what you are trying to do. Shooting 320 on Dragon is TOTALLY different than shooting 320 on MX.

Pretty sure you are dead on here David.




Lowering the ISO does not allow more light to hit the sensor. Lowering the ISO and opening up the aperture/removing ND, etc does.

Misleading is the best word I can think of to describe what is going on here and the histogram reinforces the believe that ISO changes exposure, which it does not directly.

The fact that the histogram changes when you switch ISO is damn misleading.


You are right, as is Mark...

I have yet to see any operators who are not affected by the "preview" image. Thus: Yu. ISO is metadata, but the gut reaction for anyone if you lower the ISO is adding light (and thus changing the exposure).



No. Mark's info is misleading, as is this one.

When in doubt, go back to #1.

#1. ISO does not effect exposure, the amount of light hitting the sensor.

Without this basis for understanding. No words will do your explanation justice. This concept must be a given in one's educations before attempting to explain how the monitoring path can lead to ISO adjustments to protect highlights and reduce noise.


You are right, as is Mark...

I have yet to see any operators who are not affected by the "preview" image. Thus: Yu. ISO is metadata, but the gut reaction for anyone if you lower the ISO is adding light (and thus changing the exposure).

Metadata affects how we choose to expose.

The same exposure with different metadata will be the same.

You said it best Eric.


Tailor the ISO to the values in the scene if you can.

Gunleik Groven
02-11-2014, 11:35 PM
Mark.

Catch me if I'm crazy but changing the ISO doesn't change the amount of light that hits the sensor one bit. This is all metadata of course, no physical changes that change the amount of light entering the camera like aperture, shutter speeds or NDs of course.

Maybe there is something your saying that I'm not understanding here? There is much I don't understand, this one I'm fairly sure I have correct as other users and I have gone over it several times. Gunleik would be a good man to come in here, he's been notified and might jump on this thread to add a little clarity.

You are right, as is Mark...

I have yet to see any operators who are not affected by the "preview" image. Thus: Yu. ISO is metadata, but the gut reaction for anyone if you lower the ISO is adding light (and thus changing the exposure).

Metadata affects how we choose to expose.

The same exposure with different metadata will be the same.

Phil Holland
02-11-2014, 11:45 PM
How much has RAW view changed with dragon? What rc3/rg3 ISO combo best matches the dragon RAW view?

I'll have to post an example next time I have my camera. Gunleik is overall correct with ISO 320, however, I can make Raw View look like ISO 250 and ISO 800 under different lighting conditions. It's just not as clear cut as that. It's an emulation LUT somewhat showing us the general image of what the sensor sees with a specific curve applied, so we see a normal-ish looking image which gives only the general idea of what the sensor sees.

A useful tool, especially combined with the exposure tools.

The exposure tools, stop lights, and bars are the real things to look at.

I know some "feel" the "base sensitivity" of the sensor is that Raw View, but it's just not as simple as that. That's also the wrong term all together really.

Will Keir
02-12-2014, 12:05 AM
This is a simple solution really. EDUCATE people on what is actually happening like Gunleik, David and Bjorn have pointed out. A solid understanding is the basis of a solid foundation when using the Epic. Once they understand the concept you free them to use ISO as a tool for both highlight protection and to avoid unwanted noise. They will understand exactly what is going on with their tools, empowering shooters/filmmakers to make the best choices for their vision.

Understand why it is happening, fix the problem(s), simple stuff.

"9 out of 10 times..." all the more reason to break down the basics and work up from there. If it can't be explained simply, it's a problem with the teaching, not the students.

#1. ISO does not effect exposure, the amount of light hitting the sensor. Adjusting ISO will not change your amount of highlight protection or protect you from added noise. The only way to change exposure is to add/subtract light, adjust aperture, shutter speed or use of NDs. Changing exposure in these ways can save you from unwanted noise or give you protection in your highlights.

If you keep teaching down to DP/Filmmakers, you will continue the fog of misinformation. Which started with post #2, even though it's obvious Mark has a great understanding of the Epic platform.




It all comes down to what method you choose for determining exposure - and while the ISO does not effect the actual exposure - 9 times out of 10 - it effects how the exposure is CHOSEN.

Agreed, RED needs to fix this misleading tool.



It's too bad the histogram gives this false reading of exposure.
Certainly if you are looking at the histogram - which is downstream from IRE processing and will of course change if you change the ISO.

Hans von Sonntag
02-12-2014, 12:12 AM
Its a dead horse but I have to say this thread again shows that Red's concept of ISO, RAW and metadata confuses people and leads to misconceptions. Gladly Red's sensors have enough DR to cope with unnecessary high ISOs leading to underexposure. 5 years ago this has been the conservation: what do you think is 5298 like, full 500 ASA on night exterior shots? Not really. Open up half a stop is a good idea. I rate it 320 ASA, maybe 500 for flat conditions such as shooting in a Portuguese restaurant with all those fluorescent lights.

Why can't we have that with digital cameras? Red could write 640 ASA on the Dragon sensor and off we go. Mentioning ISO 3200 as a viable way leads to very noisy pictures in night exteriors and dark interior shots. Alone the number 3200 raises expectations that won't hold up in the real world and lead to disappointment. There are plenty of posts here in the boards that clearly show that.

How many shots are postet with Neat Video treatment? Seems that to many Red and Neat Video are a natural tandem. Oh well.

Hans

Will Keir
02-12-2014, 12:19 AM
Mark's post is pretty dead on.


Really Phil? Which one?

His first post, #2 where he states ISO changes exposure?


You should lower the ISO to allow more light into the sensor. More light = cleaner image.

Quite the opposite in Post #22.


and while the ISO does not effect the actual exposure



I'd like to add to this conversation just a bit.

Usable Range.
As several people have pointed out Dragon is happy to shoot ISO 250-2000. This is what Red publishes as "fit for theatres or publication". I agree with that and this range is the basis of success when attempting to shoot "clean". You can indeed explore outside of that range however.


I would just add a guide:

250 ISO for extreme noise protection. Your cleanest image in a dark room.
2000 ISO for your extreme highlight protection shooting into the sun.

and

Good Luck shooters. See you in those dark rooms and blow out sunny days!

Phil Holland
02-12-2014, 12:37 AM
Its a dead horse but I have to say this thread again shows that Red's concept of ISO, RAW and metadata confuses people and leads to misconceptions. Gladly Red's sensors have enough DR to cope with unnecessary high ISOs leading to underexposure. 5 years ago this has been the conservation: what do you think is 5298 like, full 500 ASA on night exterior shots? Not really. Open up half a stop is a good idea. I rate it 320 ASA, maybe 500 for flat conditions such as shooting in a Portuguese restaurant with all those fluorescent lights.

Why can't we have that with digital cameras? Red could write 640 ASA on the Dragon sensor and off we go. Mentioning ISO 3200 as a viable way leads to very noisy pictures in night exteriors and dark interior shots. Alone the number 3200 raises expectations that won't hold up in the real world and lead to disappointment. There are plenty of posts here in the boards that clearly show that.

How many shots are postet with Neat Video treatment? Seems that to many Red and Neat Video are a natural tandem. Oh well.



I thought I was fairly clear in my reply. And I think what you're describing is what many have misconceptions over exactly how ISO works in all cameras.

ISO 250-2000 for clean "theater ready images". Explore other higher ISOs if looking for a unique textured look.

This doesn't need to be a difficult thing to understand or explain to others.


Here's the 4 most important concepts.

- ISO does not effect the light coming into the camera.
- ISO does effect where you "rate" your midtones.
- Expose within the recommended usable range for best results, ISO 250-2000.
- If exposure values land in the Noise Floor using higher ISO values (2500+) can produce visible image noise.


Or in a graphical explanation:



Red Dragon: ISO and FLUT Breakdown
http://www.artbyphil.com/temp/redDragonGraphics/phfx_redDragon_ISOFLUTEmulation.png
(http://www.artbyphil.com/temp/redDragonGraphics/phfx_redDragon_ISOFLUTEmulation.png)

The above graphic shows how ISO and FLUT work with the Red Dragon Sensor. The total Dynamic Range is always captured, however, when rating middle gray at a higher or lower ISO values the tonality is compressed or expanded across the captured dynamic range. The main advantage of this method being always having access to the maximum Dynamic Range and not inducing Clipping or Crushing when adjust ISO or FLUT in post.



It's interesting that you mention this:

"Red could write 640 ASA on the Dragon sensor and off we go"

As that's sort of what you can do and they do actually do. This is why most productions shoot at a chosen ISO and stick with it for the entire shoot.

I sometimes think of ISO more or less as a "film stock's look" both in texture and tonal placement.

Will Keir
02-12-2014, 12:39 AM
EXPOSURE CHECK.
VIDEO CHECK.

Phil. Would you mind explaining these two tools as you did so well with stops lights and goal posts? How to use them exactly, perhaps with some images? Is there still a need for a light meter? I'd love to get the correct information up on a sticky. Simple, only the words and explanations that matter, as a reference to send people who are interested in learning proper exposure.

It took me a couple years to learn this stuff and I still don't use all the tools in camera.

If you want to create a sticky Phil, I'd be glad to proof read and edit for simplicity. You pretty much have all the basic's covered in your post #33. Valuable stuff Phil, much appreciated and keep up the good work, reinforcing value and spreading clarity for us all.


However, the camera has on board tools that everybody should get very familiar with. It's very easy to use the tools on camera (Exposure Check and Video Check) to quickly make sure you are getting exactly what you want.

Phil Holland
02-12-2014, 12:48 AM
Really Phil? Which one?

I was referencing the last quoted post, but hopefully that didn't lead to confusion. Hopefully my explanation was clear enough to get the thoughts across.



EXPOSURE CHECK.
VIDEO CHECK.

Phil. Would you mind explaining these two tools as you did so well with stops lights and goal posts? How to use them exactly, perhaps with some images? I'd love to get the correct information up on a sticky. Simple, only the words and explanations that matter, as a reference to send people who are interested in learning proper exposure.

It took me a couple years to learn this stuff and I still don't use all the tools in camera.

If you want to create a sticky Phil, I'd be glad to proof read and edit for simplicity. You pretty much have all the basic's covered in your post #33. Valuable stuff Phil, much appreciated and keep up the good work, reinforcing value and spreading clarity for us all.

Heh. I might make a graphic and attach it to my Dragon Data Sheet thread. Much of this is covered in the Epic Operation Guide under "Appendix I: Exposure - Using False Color and ISO" and also the section on Video Check explains where various values come into play.

I'll see what I can put together. The manual is verbose for a reason, but much of this can be shown in a couple graphics with simple text.

Will Keir
02-12-2014, 01:01 AM
Phil,

Would consider making a little short BTS appendices for the manual?




I'll see what I can put together. The manual is verbose for a reason, but much of this can be shown in a couple graphics with simple text.

Hans von Sonntag
02-12-2014, 01:29 AM
Here's the 4 most important concepts.

- ISO does not effect the light coming into the camera.
- ISO does effect where you "rate" your midtones.
- Expose within the recommended usable range for best results, ISO 250-2000.
- If exposure values land in the Noise Floor using higher ISO values (2500+) can produce visible image noise.

Phil, frankly, you, I, and other seasoned reduser understand the above mentioned points. The majority don't. They dial in ISO 2000, the monitor gets visibly brighter and go happily shooting night exteriors and come back with a bunch of noisy shots. One could tell them, oh you are freshmen, don't you know that high ISO is to a certain extend good for sunny high-contrast environments and low ISOs are your best friend für night exteriors?

If they knew that the Dragon is a ISO 640 Sensor (just to grab a number) and altering the ISO is not a good idea if noise could be an issue then we had much, much less complaints about Red building noisy cameras. Arri somehow managed that and made clear that Alexa is a ISO 800 device, full stop. Telling from these boards I have the feeling that this is not the case with Red. Seen Dragon as a ISO 2000 Camera is the more spectacular story.

Porsche, for instance, publishes traditionally lower numbers in their specs as actual tests later reveal. I like this approach much more, it creates less disappointment and makes everybody more happy.





It's interesting that you mention this:

"Red could write 640 ASA on the Dragon sensor and off we go"

As that's sort of what you can do and they do actually do. This is why most productions shoot at a chosen ISO and stick with it for the entire shoot.

I sometimes think of ISO more or less as a "film stock's look" both in texture and tonal placement.

This is what I do. Epic is an ISO 320 camera, with a potential to underexpose 1 stop without exhibiting distracting noise depending on the environment. But red marketed Epic as an ISO 800 camera, which ist the meaningful edge for noise free pictures, and in the case of low light scenes it is over the edge. I chose ISO 400 for all I do with the Epic. Same as I rated 5298 as 320 ASA like 95% of the colleagues did. With film we never had those issues. But then we could not make the VF brighter and underexposing effectively the shots and telling people later: it's alle metadata, it's all in there, it's all RAW, you know... Ok. Let's check Neat Video.

I'm exaggerating of course but you get my point. Being more humble with declared ISOs would be better for Red's reputation. Noise is noise, all this talk it depends on how much you can bare, taste.... etc... is in the end meaning, feeling, faith, but not facts. Red's customer is not the low-light, available-light shooting shallow focus loving DSRL crowd.

Hans

Gunleik Groven
02-12-2014, 01:34 AM
Will.

I will not further confuse the matters with my explanations.

Phil is an excellent explainer.

I will leave this thread, with a last remark, though... :)

There is one thing ISO does not, which is: Change exposure (as in changing the amount of photons hitting the sensor)

But we use ISO to change exposure: As in rating what amount of light we will let the camera be exposed for.

ISO does not do that, the operator does.

Hans and Phil (and Mark) are spot on, in the posts I have seen.


But there are enough cooks and different language that may not communicate as well to all users in this thread for my to add any further. :)

David Battistella
02-12-2014, 03:52 AM
You know what we need.

DPs on sets. Like, I want to hear (and probably a lot more people want to hear) Peter Lyons Collester explining how he got those stunning images fo spiderman. We want to see how guys ae rating and lighting and using the tool.

Middle grey charts are nice, but I think people want to see the camera in action on real sets and see how different people are rating RED. RED could follow Mark Toia on his next shoot (id be willing to shoot and edit it) and talk to him while is in between shots abot what he is doing with a particular scene. A green screen set on one of those mega films. Bjorn Beckart on an international commercial taking yuo from the set through a post process. Some big video set wih Dino G . A photography shoot in London or Paris or Milan.

This kind of campaign would be an absolute FUD killer. Id shoot it all run and gun and explin that process too.

I have had and seen the best results when people treat RED as a FILM STOCK and light accordingly.

If Dragon actually can be rated 250-2500ISO with no penalty then we have the digital equivellent of every film stock ever made and that would be a minor miracle.

Battistella

Stephen Williams
02-12-2014, 04:07 AM
You know what we need.

DPs on sets. Like, I want to hear (and probably a lot more peoplewantto hear) Peter Lynos Collester explining how he got those stunning images fo spiderman. We want to see how guys ae rating and lighting and using the tool.

Middle grey charts are nice, but I think people want to see the camera in action on real sets and see how different people are rating RED. RED could follow Mark Toia on his next shoot (id be willing to shoot and edit it) and talk to him while is in between shots abot what he is doing with a particular scene. A green screen set on one of those mega films. BjornBeckart on an international commercial taking yuo from the set through a post process. Some big video set wih Dino G . A photography shoot in London or Paris or Milan.

This kind of campaign would be an absolute FUD killer. Id shoot it all run and gun and explin that process too.

I have had and seen the best results when people treat I as a FILM STOCK and light accordingly.

If Dragon actually can be rated 250-2500ISO with no penalty then we have the digital equivellent of every film stock ever made and that would be a minor miracle.

Battistella

I did some green screen tests with Dragon last week, 400 ISO with 7:1 compression was ideal. Quite similar performance noise wise as another high end camera. I would not have wanted to use more than 5:1 with MX

Hans von Sonntag
02-12-2014, 04:45 AM
I did some green screen tests with Dragon last week, 400 ISO with 7:1 compression was ideal. Quite similar performance noise wise as another high end camera. I would not have wanted to use more than 5:1 with MX

Thanks Stephen. Your findings regarding ISO matches mine pretty well. For cleanest results exposing near to the "native" sensitivity is meaningful.

----

I use LUTs and grain intensively in my Smoke systems. Grain can be added later in subtle dose-rates. No reason to introduce grain in the footage unnecessarily. I'm sure Dragon will end up in my hands as an ISO 800 camera for most things like the MX has been a ISO 400 camera. However, for GS opening aperture just about a stop makes sense.

Hans

Mark L. Pederson
02-12-2014, 05:06 AM
Really Phil? Which one?

His first post, #2 where he states ISO changes exposure?



Quite the opposite in Post #22.





I would just add a guide:

250 ISO for extreme noise protection. Your cleanest image in a dark room.
2000 ISO for your extreme highlight protection shooting into the sun.

and

Good Luck shooters. See you in those dark rooms and blow out sunny days!

Will - you are taking me out of context - when I said "You should lower the ISO to allow more light into the sensor. More light = cleaner image." I was SPECIFICALLY responding to a question a user posted where he asked if he should leave ISO at 2000 and then limit the light with NDs vs lowering the ISO. You should re-read that post. I guess I should have said "You should lower the ISO vs. keeping at 2000 and adding ND filters as to allow more light into the sensor. More light = cleaner image." - but the guys question was quoted in my response.

David Battistella
02-12-2014, 05:24 AM
I did some green screen tests with Dragon last week, 400 ISO with 7:1 compression was ideal. Quite similar performance noise wise as another high end camera. I would not have wanted to use more than 5:1 with MX


Let's do it.

Keep me posted on your next shoot.

Battistella

Mark L. Pederson
02-12-2014, 05:24 AM
This is a simple solution really. EDUCATE people on what is actually happening like Gunleik, David and Bjorn have pointed out. A solid understanding is the basis of a solid foundation when using the Epic. Once they understand the concept you free them to use ISO as a tool for both highlight protection and to avoid unwanted noise. They will understand exactly what is going on with their tools, empowering shooters/filmmakers to make the best choices for their vision.

Understand why it is happening, fix the problem(s), simple stuff.

"9 out of 10 times..." all the more reason to break down the basics and work up from there. If it can't be explained simply, it's a problem with the teaching, not the students.

#1. ISO does not effect exposure, the amount of light hitting the sensor. Adjusting ISO will not change your amount of highlight protection or protect you from added noise. The only way to change exposure is to add/subtract light, adjust aperture, shutter speed or use of NDs. Changing exposure in these ways can save you from unwanted noise or give you protection in your highlights.

If you keep teaching down to DP/Filmmakers, you will continue the fog of misinformation. Which started with post #2, even though it's obvious Mark has a great understanding of the Epic platform.



Agreed, RED needs to fix this misleading tool.

Will - it's actually not a hard concept to understand. We've been doing it for decades.

35mm motion picture film - it has an ISO rating on the can. Let's say it's 500. That's a recommended ISO. That number does NOT effect how much light goes into the motion picture film camera. Only aperture, filters and shutter do (sound familiar). It's a recommendation for how a DP and/or Gaffer should set his/her light meter as to measure light to set an exposure - aka exposure method.

Now, some DPs would rate that same film stock at 640 - some at 320 - and by changing the rating - changing the ISO - no more or less light came into the camera - it's just a setting on the light meter ...

BUT .....

By changing the rating on the light meter .... his/her CHOICE (method) of exposure is changed as the light is now metered differently.

We now have the other elephant in the room with respect to monitor path - as we only had a flickering black and white shit video tap attached to an viewfinder for the longest time in film. So nobody ever argued with the exposure setting.

Now ... you have to ask yourself ... all those movies ... THOUSANDS of movies shot in film ... no histogram. No stoplights. No monitor path. No false color. How did they manage to get the right exposure?

It was their job to understand ISO and rating the light meter - and how THEIR EXPOSURE METHOD (using a light meter) created results on a GIVEN FILM STOCK.

MX is a film stock.

DRAGON is a film stock.

The last Reducation class I taught I asked the class to raise their hands if they understood what Contrast Ratio meant. One person raised their hand and had the wrong answer. I believe that the DSL and digital camera movement has pushed the "point and shoot" and "WYSIWYG" thing so much ... the newer generations are sadly missing the most fundamental basics of cinematography/photography.

And that is most likely why still photographers find RAW easy. Because still photographers typically have a very solid foundation of the fundaments of photography. They are focused on their choice of settings and exposure method instead of a monitor path.

Paul E. McCarthy
02-12-2014, 06:14 AM
Will - it's actually not a hard concept to understand. We've been doing it for decades.

35mm motion picture film - it has an ISO rating on the can. Let's say it's 500. That's a recommended ISO. That number does NOT effect how much light goes into the motion picture film camera. It's a recommendation for how a DP and/or Gaffer should set his/her light meter as to measure light to set an exposure.

Now, some DPs would rate that same film stock at 640 - some at 320 - and by changing the rating - changing the ISO - no more or less light came into the camera - it's just a setting on the light meter ...

BUT .....

By changing the rating on the light meter .... his/her CHOICE of exposure is changed as the light is now metered differently.

We now have the other elephant in the room with respect to monitor path - as we only had a flickering black and white shit video tap attached to an viewfinder for the longest time in film. So nobody ever argued with the exposure setting.

Now ... you have to ask yourself ... all those movies ... THOUSANDS of movies shot in film ... no histogram. No stoplights. No monitor path. No false color. How did they manage to get the right exposure?

It was their job to understand ISO and rating the light meter - and how THEIR EXPOSURE METHOD (using a light meter) created results on a GIVEN FILM STOCK.

MX is a film stock.

DRAGON is a film stock.

The last Reducation class I tought and asked the class to raise their hands if they understood what Contrast Ratio meant. One person raised their hand and had the wrong answer. I believe that the DSL and digital camera movement has pushed the "point and shoot" and "WYSIWYG" thing so much ... the newer generations are sadly missing the most fundamental basics of cinematography.

Mark is Correct.

And the application of this is called shooting the "Toe" or shooting the "Shoulder",

Its a common practice for film guys through history until the Vision Stocks came out. Most DPs shot only 200TASA (5293) stock and never set there light meters to 200ASA ever.
They would shoot day and night because the early 500ASA was so grainey or as we say now noisey (sad that grain is called noise, so negative)and shooting different stocks was always jarring in the edit.

If you are going for a darker look, night interior, you shot test for the toe, the bottom of the stocks DR and sensitivity. You are going for blacks, skin exposure and protecting grain,not concerned with highlights, it not interior and you can put practicals on dimmers.

You might find that rating the film at 500 gave you much better results because you found some extra DR in this chemical batch of film which ranged quite a bit in the 90s. From 200ASA to 500ASA is a doubling of light. That is a huge amount a light at 200ASA you don't need now.

And vice versa with shooting "shoulder."

If you are going for skies or highlights or windows, you shoot and test for the Shoulder. And rate the same stock accordingly maybe at 100ASA to get that cloud detail.

Just because DR is there, doesn't mean that that info has to go on the screen, you get to choose, that's your call.



find your Toe or Shoulder sweet spot.

I decide to shoot the shoulder or toe and ETTR.
I never had a problem getting a black in post so I tend to open up for Night interiors and stop down for day exteriors

If 800 is clipping, always ND if you can to the native rating of the camera that's always the best, if youre out of ND and you need to roll the ASA down to hold the skies just do it. Your contrast will go up, so pull some out in your look settings,

Scott Crawley
02-12-2014, 06:41 AM
I'm with Mark on this just as I believe in his suggestions about RAW view. (See thread: Truth or False Color (http://www.reduser.net/forum/showthread.php?112571-Truth-or-False-Color).)

It may be time to assign the chips a sensitivity and color temp rating just like was done with film stock. It would probably be more helpful in the long run if the ISO scale were not used in rating them for a number of reasons, but that might be too much too fast.

People need to stop thinking of the chip as having adjustable sensitivity. It does not, but including an ISO adjustment apparently misleads many to believe exactly that. It may be time for the elimination of the ISO control slider. In it's place, expand the FLUT slider to incorporate the full range of the current ISO adjustment and give it a coarse and fine control.

Mark L. Pederson
02-12-2014, 06:54 AM
People need to stop thinking of the chip as having adjustable sensitivity. It does not, but calling that adjustment ISO apparently misleads many to believe exactly that. It may be time for the elimination of the ISO control slider. In it's place, expand the FLUT slider to incorporate the full range of the current ISO adjustment and give it a coarse and fine control.

No. That's crazy IMO.

EVERY digital camera let's you adjust ISO - and it's a powerful tool to manage your DR. And while SOME people struggle to understand it - MANY of us - understand it and leverage it.

I think this whole issue is about EDUCATION.

It's not a RED thing - you can adjust ISO on the Alexa, F65, F55, etc. etc. - it's a result of RED facilitating more people having access to a powerful tool and having an open, public forum.

Again, back in 35mm days - you had to know your shit before someone let you choose a F stop on the lens and let hundreds and hundreds of dollars worth of celluloid rip through a magazine.

Today ... these tools are so powerful that you can get a "reasonable" image without knowing anything -

BUT - if you want to leverage the tool and make GREAT images ... You need to know your shit. You need to know the fundamentals. If it is confusing to you - keep asking - read books - seek out a mentor - get a shitty job under an expert and then pay attention to every single thing he or she does.

Go to Reducation :)

When I first got my hands on Dragon - I thought - WOW - this is REALLY like film. Screw the histogram - get a light meter if you want to get everything out of this camera!!!

Making the camera "dumber" - or eliminating powerful tools that some people have trouble understanding is NOT the answer.

Ask me anything. I'm here - I'll do whatever I can to help.

Scott Crawley
02-12-2014, 07:07 AM
You have clearly thought this out much more than I, and have a deeper understanding so please bear with me. Thank you for entertaining my questions and helping me to navigate this.

The ISO control is a misnomer. I simply suggested that it be given a more appropriate name, not to eliminate the tool or limit the control. What could be wrong with eliminating that source of confusion? The ISO control and the FLUT control are the exact same adjustment, are they not? My understanding is that they are neither ISO nor gain control. Is that correct?

It may seem like a dumbing down but it really isn't. Educated digital shooters will understand how to push the chips just as they knew how to push a film stock, and less re-education will have to be done if the terminology is not misused or re-purposed.

Mark L. Pederson
02-12-2014, 07:35 AM
The ISO control is a misnomer. I simply suggested that it be given a more appropriate name, not to eliminate the tool or limit the control. What could be wrong with eliminating that source of confusion? The ISO control and the FLUT control are the exact same adjustment, are they not? My understanding is that they are neither ISO nor gain control. Is that correct?

Nope. It's NOT a misnomer. It's exactly what it should be called - it's how almost every digital camera works - and it's how photographers and cinematographers have worked for decades on film and now on digital.

From Wikipedia ISO -

"In digital camera systems, an arbitrary relationship between exposure and sensor data values can be achieved by setting the signal gain of the sensor. The relationship between the sensor data values and the lightness of the finished image is also arbitrary, depending on the parameters chosen for the interpretation of the sensor data into an image color space such as sRGB.
For digital photo cameras ("digital still cameras"), an exposure index (EI) rating—commonly called ISO setting—is specified by the manufacturer such that the sRGB image files produced by the camera will have a lightness similar to what would be obtained with film of the same EI rating at the same exposure. "

I'm going to go out on a limb here -

I think that any person who is confused by what ISO does or doesn't do on a RED camera - does not know how to use a light meter to measure light - and thereby - would have no idea how to set exposure for a film camera with a given filmstock (with a recommended ASA/ISO rating).

Because ... IF they knew how to do that ... they would understand exactly what is going on with a RED camera with ISO. (or an Alexa, F65, F55, etc etc,)

Would you not agree?

Is there ANYONE out there that is confused by ISO that knows how to choose an exposure correctly if I handed them a 35mm camera loaded with Vision 3 and a light meter?

So again ... I think this is about EDUCATION - and I think what is SADLY MISSING these days is the very fundamentals of photography/cinematography.

Scott Crawley
02-12-2014, 07:45 AM
Nope. It's NOT a misnomer. It's exactly what it should be called - it's how almost every digital camera works - and it's how photographers and cinematographers have worked for decades on film and now on digital.

From Wikipedia ISO -

"In digital camera systems, an arbitrary relationship between exposure and sensor data values can be achieved by setting the signal gain of the sensor.

I don't know if we need a Red Engineer to clear this up but I believe this is incorrect.

Also according to WIKI (http://en.wikipedia.org/wiki/Gain):
"In electronics (http://en.wikipedia.org/wiki/Electronics), gain is a measure of the ability of a circuit (http://en.wikipedia.org/wiki/Electrical_network) (often an amplifier (http://en.wikipedia.org/wiki/Amplifier)) to increase the power (http://en.wikipedia.org/wiki/Power_(physics)) or amplitude (http://en.wikipedia.org/wiki/Amplitude) of a signal (http://en.wikipedia.org/wiki/Signal_(electrical_engineering)) from the input to the output, by adding energy to the signal converted from some power supply (http://en.wikipedia.org/wiki/Power_supply)."

Does the ISO setting on Red actually boost the electrical signal coming from the sensor or does it simply redefine the relationship of the response curve to the scale?

Terry VerHaar
02-12-2014, 07:48 AM
Does the ISO setting on Red actually boost the electrical signal coming from the sensor...
NO


or does it simply redefine the relationship of the response curve to the scale?

YES

:smiley:

Mark L. Pederson
02-12-2014, 07:48 AM
Does the ISO setting on Red actually boost the electrical signal coming from the sensor or does it simply redefine the relationship of the response curve to the scale?

Sure it does - to the monitor path only - but since we record RAW ... not to the recorded image. Make sense?

Wiki is not so up to date on the RAW world :)

And again, this is how every RAW camera works that I have touched. It's not bad terminology from RED.

Scott Crawley
02-12-2014, 07:56 AM
:blink:

OK. Please define FLUT. Is it same, or different?

~and thanks a ton.


Sure it does - to the monitor path only - but since we record RAW ... not to the recorded image. Make sense?

Wiki is not so up to date on the RAW world :)

And again, this is how every RAW camera works that I have touched. It's not bad terminology from RED.

Gunleik Groven
02-12-2014, 08:21 AM
FLUT = ISO (but in decimal increments)

FLUT +1 = (for example) ISO 400 -> 800

Scott Crawley
02-12-2014, 08:31 AM
Sure it does - to the monitor path only - but since we record RAW ... not to the recorded image. Make sense?

Wiki is not so up to date on the RAW world :)

And again, this is how every RAW camera works that I have touched. It's not bad terminology from RED.

So when Graeme says that the old concept of ISO doesn't really apply to digital, what exactly does he mean do you think? (I don't know if I can find a link in the archive. It was years ago. I will look.) Was he just referring to the fact that the MX does not exactly test out to 320 ISO or is there a more fundamental difference?


FLUT = ISO (but in decimal increments)

FLUT +1 = (for example) ISO 400 -> 800

Thanks. That is what I thought.

I guess the A/D converter in my head is getting an overdue an upgrade. ;-)

Gunleik Groven
02-12-2014, 08:44 AM
So when Graeme says that the old concept of ISO doesn't really apply to digital, what exactly does he mean do you think? (I don't know if I can find a link in the archive. It was years ago. I will look.) Was he just referring to the fact that the MX does not exactly test out to 320 ISO or is there a more fundamental difference?


as far as I can remember and understand (but Graeme could well jump in and correct me), he was refering to the fact that you do not change the sensitivity of a sensor.

Let's say that filmstocks have 16 stops with+8/-8 independent of ISO rating, an 800 stock will have an equal over/under distribution as a 400, but the 800 wil manage one more stop in the bottom than the 400 one more in the top. (these are theoretical stocks...)

While with a sensor, you do not actually change the sensor (stock), so it will always clip and always go black at the same photon-levels, independently of what "ISO" you rate it at. The ISO just changeswhere within that range you put middle gray, from let's say +8/-8 to +7/-9

So the term does not give the same result when referred to stocks as it does to sensors. Unless you think of the different ISO settings as "pressing" the same stock. But even in that analogy, it is not a very precise equation, as film and sensors "see/respond" to light in very different ways.

Mark L. Pederson
02-12-2014, 09:02 AM
So the term does not give the same result when referred to stocks as it does to sensors.

Yes.

But ... for the purpose of an EXPOSURE METHOD - it is VERY common to use ISO the same way cinematographers & photographers have for the last 60+ years.

Just think of the sensor as the film stock.

If you are using a light meter as part of your exposure method - you are using ISO in your exposure method.

If you are using the Histogram on a RED camera as part of your exposure method - you are using ISO in your exposure method.

If you are using a monitor as part of your exposure method - you are using ISO in your exposure method.

Gunleik Groven
02-12-2014, 09:09 AM
I agree with all the above Mark. In fact I agree with all I have read from you in this thread.

That is why I try to stay out :)

I was walking around thinking about linear vs nonlinear lightresponse and how that affects the "pressing of stocks", but my brain said: Don't go there! :)

Hahahaha

It is pretty much the same point of this and the false color thread, though. :)

And what I see too often, is that people think of changing ISO like changing stock.

I can see from these threads how what I think of as simple concepts, can be confusing...

I'll duck again now. Promise! :)

Mark L. Pederson
02-12-2014, 09:18 AM
I agree with all the above Mark. In fact I agree with all I have read from you in this thread.

That is why I try to stay out :)

Don't stay out. Clearly some people understand some explanations better from some folks over others.

Again, I think the issues of confusion are not about the high level stuff like - linear vs nonlinear light response - I think it's about the fact the younger generations are getting powerful tools that can work for them without them understanding how they work. And without a solid foundation of very basics of photography - there will be confusion.

In the old days - you had to work so hard and learn first to get the right and/or opportunity to use the tool (film camera) - today you just pull out your amex and you are an owner/operator. That's not a bad thing at all - it's democratization of technology - it empowers creatives. Now you can own the same camera that was used to shoot Michael Bay's next blockbuster. That's CRAZY!

But just buying the camera does not equal an understanding of the fundamentals of cinematography/photography. And IF you want to go advanced - (linear vs nonlinear light response for example) - you NEED to understand the basics ... or you will be fucked.

Scott Crawley
02-12-2014, 09:23 AM
Yes it is my understanding that the analogy applies. Each line of chip (M, MX, Dragon) has it's own response curve that defines it just as each film stock has it's own defining response curve.

You do not actually change the sensitivity of a film stock either. When I set the ISO on my old film Pentax, what I am doing is changing the way the internal light meter responds. My understanding is that this is the same with Red. The difference is that the ISO setting can also directly effect the way the captured values are displayed, which does not happen with film.

Am I still on track?



as far as I can remember and understand (but Graeme could well jump in and correct me), he was refering to the fact that you do not change the sensitivity of a sensor.

Let's say that filmstocks have 16 stops with+8/-8 independent of ISO rating, an 800 stock will have an equal over/under distribution as a 400, but the 800 wil manage one more stop in the bottom than the 400 one more in the top. (these are theoretical stocks...)

While a sensor, you do not actually change the sensor (stock), so it will always clip and always go black at the same photon-levels, independently of what "ISO" you rate it at. The ISO just changes the rating from let's say +8/-8 to +7/-9

So the term does not give the same result when referred to stocks as it does to sensors. Unless you think of the different ISO settings as "pressing" the same stock. But even in that analogy, it is not a very precise equation, as film and sensors "see/respond" to light in very different ways.

Gunleik Groven
02-12-2014, 09:23 AM
But just buying the camera does not equal an understanding of the fundamentals of cinematography/photography. And IF you want to go advanced - (linear vs nonlinear light response for example) - you NEED to understand the basics ... or you will be fucked.

Could not agree more.

If I may... What seems to generate some confusion here, is that two issues are confused.

1. What does ISO mean on a digital camera
2. How is ISO used for exposure
(and as a possible actually unrelated 3.) What is "base" ISO of camera X

Gunleik Groven
02-12-2014, 09:29 AM
Yes it is my understanding that the analogy applies. Each line of chip (M, MX, Dragon) has it's own response curve that defines it just as each film stock has it's own defining response curve.

You do not actually change the sensitivity of a film stock either. When I set the ISO on my old film Pentax, what I am doing is changing the way the internal light meter responds. My understanding is that this is the same with Red. The difference is that the ISO setting can also directly effect the way the captured values are displayed, which does not happen with film.

Am I still on track?

You are on track.

Well... Much of the same happens if you press a filmstock a stop and a sensor a stop. The noise/precission/color-renderition characteristics are changed. Thus if you edit a continuus "dialogue" scene where the DOP have used (let's say) ISO 400 for one person and 1600 for the other, it will probably cut quite badly, even though you have normalized the developed levels with ISO in a way that makes developed skin-levels "equal", the "character" of the images are not vaguely similar.

I frequently used to underexposure MX (ie: High ISO) to soften my images and get a different and "fatter" kind of colors... :)

It is fun that we have this conversation, as I am looking through images to put up on my website-to-be... :)

(this is one of my early Epic exposures...)

http://static7.oneclick.gunleik.com/2014/02/9cd75b6c8fc1ad9507835c6338423171c0617f84.jpg

Scott Crawley
02-12-2014, 09:31 AM
Again, I think the issues of confusion are not about the high level stuff like - linear vs nonlinear light response - I think it's about the fact the younger generations are getting powerful tools that can work for them without them understanding how they work. And without a solid foundation of very basics of photography - there will be confusion.

Sure, but it is not an age related thing. Speaking only of myself; I am not of a "younger generation". I do not have an advanced degree in photography or cinematography. I learned what I could in schools, through mentoring and independent study. I believe that I have a pretty solid understanding of film. What I and I believe many others are lacking is confidence in what we know and perhaps a completeness of understanding. In a word, mastery.

Correction Two words: Mastery and Certification, as I do not feel i have been thoroughly tested. Getting back to Mark's earlier point, Reducation could help with some of that. :-)

Mark L. Pederson
02-12-2014, 09:34 AM
If I may... What seems to generate some confusion here, is that two issues are confused.

1. What does ISO mean on a digital camera
2. How is ISO used for exposure
(and as a possible actually unrelated 3.) What is "base" ISO of camera X

Yes. And this is why I keep beating the term EXPOSURE METHOD because people use different methods for choosing an exposure.

I try to tell people:

The sensor doesn't care what the ISO setting is - but usually the person choosing the exposure cares very much. It depends on the method they choose to use to choose that exposure. And MOST of the tools are in fact, effected by an ISO choice - light meter, histogram, monitor path.

So ... it doesn't change what the sensor records - but it changes MOST methods for choosing the aperture, shutter, filters that DO effect what the sensor records.

I actually HATE when people say "it's JUST meta-data" - as if it's meaningless - when in fact - it's CORE to understanding the fundamentals.

Mark L. Pederson
02-12-2014, 09:46 AM
Sure, but it is not an age related thing. Speaking only of myself; I am not of a "younger generation". I do not have an advanced degree in photography or cinematography. I learned what I could in schools and through mentoring and believe that I have a pretty solid understanding of film. What I and I believe many others are lacking is confidence in what we know and perhaps a completeness of understanding. In a word, mastery.

Understood it's not about age - the generation comment was more based on what people have access to now vs. when I was young and wanted to make movies.

I am certainly NOT saying anyone needs "an advanced degree in photography or cinematography" in fact - I'm saying the opposite. You need to understand the very basics.

Setting Aperture / Shutter Speeds / Depth of Field / FOV / ISO / using a light meter / dynamic range / contrast ratios, etc. - and what all them do and effect.

You can't get to the mastery if you don't truly understand the basics. I'm sure that you do - but it is clear to me that a good number of folks are missing an understanding of at least some of the basic things.

Elsie N
02-12-2014, 09:52 AM
...
I frequently used to underexposure MX (ie: High ISO) to soften my images and get a different and "fatter" kind of colors... :)

...

Gunliek, are you referring to the thickness of the histogram when you say fatter? I've noticed that sometimes I get a very thick readout and other times it is very slim. I always assumed it had to do with the amount of light hitting the sensor but your statement suggests it may have to do with ISO?

David Battistella
02-12-2014, 09:54 AM
You know what is weird.

Since the very first day of owning a red (early adopter 758) and right up until today, the only place to see RAW view is in the camera.

You can not see raw view (or the specific RAW view lut) on anything other than the camera or camera monitoring devices. That means a DP uses that image as a reference image and will never have the chance to his reference image it again.

so maybe that needs to change, maybe it doesn't .

discuss...


battistella

Gunleik Groven
02-12-2014, 09:57 AM
I agree with all that.

I try (knowingly) to distinguish "ISO" from "exposure" in what I write as
Exposure = photon hitting the sensor
ISO = interprets the sensor data into something viewable (part of that chain, I know, but an important one)

When I see all the requests for ISO tests, I get a bit pissed at times. Because I can make a noisy or noisefree image under "any" ISO, just by controlling the exposure.
One thing I want to do with the Bristol files, unless Geoff does that, is to normalize all the exposure in 1-stop increments to the base-exposure with ISO operations.
That way people can see what noise you get "a given ISO".

I am reluctant to do that though, because I can foresee the responses to the results. Because in doing that, high-ISO images will be noisy... :)
And people do not WANT the 6400 exposure to have more noise than the 200. And using all that energy telling people that this is actually "fantastic" and "proof that things work like they should", and that this does not make "Dragon bad in lowlight", is sometimes a drag... :)

They could download the files and postulate the results easily themselves, but I think it could be a useful thing to do, for those who can interpret the data.

Likewise I think it would be cool to do resampling tests to UHD and 1080, but some people do not get that "smoother" does not equal "noiseless".

Graeme had a nice little post on read-out-noise, which was very enlightening to me.
Read-out noise is equal at all exposures, but becomes a higher percentage of the total image at underexposures than "good" exposures.

Another thing that people do not seem to think too much about either is how the color hue/saturation-characteristics can change drastically under different exposure levels, even under the same light.


I would say I HATE when people say that ANY metadata is "just metadata".

Back when the R1 M came out, many used it as a video-cam. Even film-photographers. And I had files sent to me, being the "RED-geek".

One example I always remember was from a big-film set with enough lights and a 100 KW truck. They were filming an indoor night bar-scene. Typical cliches with dancing girls and all, and they wanted the scene to be blue.
They started off with WB'ing the camera (as they had tungsten-lights, right+), and then lit from the monitors.

They had all the gels and power in the world, but still they managed to seriously underexpose the blue-channel in a blue scene with more than enough lights available, because of metadata (in this case WB and ISO) misleading them in their exposure decisions.

This is vastly improved with the Dragon. It allows for a lot more "stupidity", but still intent wins over accident. :) And even though the files are incredibly more "better", you get further by doing it "right for your scene according to camera".
But for intent, you have to understand how it works... :)

Rant off...

Gunleik Groven
02-12-2014, 09:58 AM
Gunliek, are you referring to the thickness of the histogram when you say fatter? I've noticed that sometimes I get a very thick readout and other times it is very slim. I always assumed it had to do with the amount of light hitting the sensor but your statement suggests it may have to do with ISO?

Nope.

i was referring to how the channels saturate.

The example posted above is an example of serious underexposure...

Scott Crawley
02-12-2014, 09:59 AM
That means a DP uses that image as a reference image and will never have the chance to his reference image it again.

Load the shot back up into a mag and playback on the camera if you need to, though I am unsure why you would need to.

David Battistella
02-12-2014, 10:02 AM
Not to practical three months later in a DI.

battistella


Load the shot back up into a mag and playback on the camera if you need to, though I am unsure why you would need to.

Gunleik Groven
02-12-2014, 10:05 AM
Not to practical three months later in a DI.

battistella

Could be...

Bt it is a good point to marks point that we want the "metering" from the RAW view in the exposure tools, not the image... :)

Mark L. Pederson
02-12-2014, 10:05 AM
You know what is weird.

Since the very first day of owning a red (early adopter 758) and right up until today, the only place to see RAW view is in the camera.

You can not see raw view (or the specific RAW view lut) on anything other than the camera or camera monitoring devices. That means a DP uses that image as a reference image and will never have the chance to his reference image it again.

so maybe that needs to change, maybe it doesn't .

discuss...


battistella

Just eliminate RAW view - once the EXPOSURE tool are corrected to work the way they should - (RED is looking into this and testing now) - there is ZIP, ZERO, ZILCH reason to have RAW view other than to confuse people.

Please prove me wrong if you have any idea WHY this should stay -

David Battistella
02-12-2014, 10:34 AM
Sorry for the long post but please take the time to read it.

There should be a view (LOG, RAW, PRO VIEW, B&W whatever) separate from the look placed on a monitoring path that allows a person who understands the tools, the DP, gaffers, operators, etc. which allows you to see "into the negative" a bit better on set.

The problems with applying LUTS and looks on set , etc, like Gunleik explained in his example of a large budget set that lit to the monitor is that this attitude moves us away from measuring light and understanding how the sensors photo buckets are absorbing the light hitting it (like light on silver at the film plane) (as an aside, getting rid of ISO is like saying let's get rid of the T-stop, f stop is fine).

otherwise working with. RED is like working with a 5D and that picture on the screen and the monitor is all you are going to get.

I'm anticipating your response will be that if the underlying tools, Exposure, ire, zebra, are all working on RAW, then the most critical factor is that a base sensitivity has to be established for the sensor.

If the dragon sensor indeed claims to replace all film stocks from 250-2000ISO , then they give users maximum flexibility to rate the sensor at whatever ISO they like then I would say that opens it up to a lot of subjective interpretation (and also creative choice). But I do think it is the manufacturers responsibility (like kodak or Fuji would do) to say, at this ISO, with daylight (or tungsten) sources, metered and lit according to industry standards, will yield the sharpest images with the most accurate color.

Like in film the creative choices can come in, push pull, 1,2stops, use filtration, bleach bypass (digital version) becomes a creative choice that deviates from the baseline set by the sticker on the film can.

i feel it is important that RED stay on their course to be the digital replacement for film, therefore a continuation of that language is necessary to continue that tradition (like a nikon D700 does not change the language from an F3).

In using film, the DP is the person responsible for how the light hits the film plane, the best ones actually work in blindness with their knowledge of how the film and processing would react. They had a shit BW video tap but made great images. Why should that knowledge or method deviate too much because of an HD monitor onset! which represents about 1/6 of the data being captured.

RED is in more peoples hands, but few people have really taken the time to know and understand it enough to be able to shoot it blind folded (in the sense of knowing how strictly a metered scene will interact with the sensor). Is that RED's fault, no. That is the fault of an industry which has become lazy toward craft (at the middle and lower end).

So give pro DP's the a professional tool and let them have a sensor view, they need it to help people understand that there is more going on under the hood than what the client sees on the monitor.

Battistella

Mark L. Pederson
02-12-2014, 10:42 AM
There should be a view (LOG, RAW, PRO VIEW, B&W whatever) separate from the look placed on a monitoring path that allows a person who understands the tools, the DP, gaffers, operators, etc. which allows you to see "into the negative" a bit better on set.
Battistella

Well ... please define what looking "into a negative" means to you?

I'm not saying I disagree - but - since you MUST perform RGB processing to view it - you have to make a choice.

So ... what exactly do you want to see in this "LOG, RAW, PRO VIEW, B&W whatever" - and tell me EXACTLY how you want use it and why.

David Battistella
02-12-2014, 10:43 AM
Could be...

Bt it is a good point to marks point that we want the "metering" from the RAW view in the exposure tools, not the image... :)

i really have not used any of the exposure tools outside of RAW view mode. Why would I care what is going on in the meta data when all I care about is going on at the sensor level? Give me a crappy image with all the tools available and set up and send whatever you want downstream to the pipe that feeds the non non critical monitors (commercial client). I don't care about the meta data views. I leave my camera set to 320, 5000k and work from there, but I've taken the time to understand how the machine works too.

If it needs to be dumbed down for some DPs or clients, fine, do it on another feed.

Battistella

D Fuller
02-12-2014, 10:50 AM
Yes it is my understanding that the analogy applies. Each line of chip (M, MX, Dragon) has it's own response curve that defines it just as each film stock has it's own defining response curve.

You do not actually change the sensitivity of a film stock either. When I set the ISO on my old film Pentax, what I am doing is changing the way the internal light meter responds. My understanding is that this is the same with Red. The difference is that the ISO setting can also directly effect the way the captured values are displayed, which does not happen with film.

Am I still on track?

Yes you are on track. But I'd modify a couple of these observations. The ISO setting on your Pentax changes the way your light meter responds, that's true. But it's important because it changes that way you will expose the film. And it very much changes that way the captured values are displayed (though not until after developing and printing).

To quote myself from another thread: After some detours, I've come to think about exposure on Red in much the same way that I used to think about it on film. A film has a fixed sensitivity (ISO), but knowing that, I can choose to expose at a different ISO and push or pull in post (either chemically or in transfer or printing). I know the image will have different characteristics if I do that, and that's part of my exposure calculation. I can over expose and under-develop, and get more highlight compression and more shadow detail. I can under expose and overdevelop and get more contrast, more grain, but with the risk of blocked highlights. All from the same film stock.

I expose Red with very similar thinking, and that's where ISO has become important again -- not the camera's ISO setting, but ISO as a reference for light levels in front of the lens. I know that the sensor is about 320 ISO native, but I don't love the completely-clean image I get at 320 for most things. At 800, I get a bit of very pleasant noise, which I like, and the added benefit of some headroom that lets me roll the highlights off nicely. But for things like tabletop and package shots, I usually want a "fatter negative" with more color and a bit less noise, so I expose for 640 or 500, knowing I have to watch the highlights more carefully, but knowing that it will do things to the image that I want. Or as with Gunleik's image above, I can underexpose and get an image where darks cluster together and mix with noise a bit, and the hilights occupy most of the long slope of the tonal curve. All with a sensor that has a fixed response.

What I can't do is expect that a scene I "shoot at ISO 400" will look like a scene that I "shoot at ISO 3200". That won't happen. (And it won't happen with any other camera on the market either, by the way.) Light matters.

Mark L. Pederson
02-12-2014, 10:50 AM
In using film, the DP is the person responsible for how the light hits the film plane, the best ones actually work in blindness with their knowledge of how the film and processing would react. They had a shit BW video tap but made great images. Why should that knowledge or method deviate too much because of an HD monitor onset! which represents about 1/6 of the data being captured.

Battistella

That knowledge and method does not deviate at all.

If a DP can expose 35mm film without a monitor and nail the exposures - than that DP already has the exact understanding of how to work with a RED camera - sensor = film stock - and like every DP does when a new film stock is released that they are interested to use - they shoot a few simple tests using their specific exposure method and subjectivity - and they understand exactly what to do.

And those folks do not need a histogram, monitor, false color/exposure meters or stop lights to nail their exposure perfectly every time. I've seen it done. Lots of the big dogs hate monitors on set.

Having more tools for exposure is GREAT - as long as everyone understands them - and they work as advertised. We are getting there :)

David Battistella
02-12-2014, 11:00 AM
So ... what exactly do you want to see in this "LOG, RAW, PRO VIEW, B&W whatever" - and tell me EXACTLY how you want use it and why.

I want a flat logish style image shows me something more complete than linear light. RAW as it is or RC4/REDlog film would be perfect.

I want to see this so I have a sense of the total frame and I can later decide what I have in the blacks and the highlights so that I can adjust later in the grade, know what is blown out and what can not be recovered.

I want the brightness of that image to be as close to the best possible image the camera can produce (sensor native 5000K, baseline ISO accurate to metered light, noiseless image) that yields the sharpest image with the best color fidelity and the widest latitude, without coloring it up for me. (If I want to deviate from that I will do my own testing and cook my own look, but as a start I want to know what the manufacture thinks will make the camera/film stock shine in terms of optimum technical precision, by adding a simple s-curve to make one lights easy.

I want two monitoring paths, the professional one as above with menus, guides etc and a clean cooked look for clients.

I want histogram, goal posts and Exposure tools. No ire, no zebra or any of that crap leftover from shitty video cameras.

battistella

David Battistella
02-12-2014, 11:08 AM
That knowledge and method does not deviate at all.


this goes to my point of RED taking a leadership position as the replacement of digital film. I feel they should be on this like a pit bull on a bone. Needs to be established right now, with this sensor and this system. Put the eggs in that basket.

You hear me on that one RED. :)



battistella

Elsie N
02-12-2014, 11:14 AM
Yes you are on track. But I'd modify a couple of these observations. The ISO setting on your Pentax changes the way your light meter responds, that's true. But it's important because it changes that way you will expose the film. And it very much changes that way the captured values are displayed (though not until after developing and printing).

To quote myself from another thread: After some detours, I've come to think about exposure on Red in much the same way that I used to think about it on film. A film has a fixed sensitivity (ISO), but knowing that, I can choose to expose at a different ISO and push or pull in post (either chemically or in transfer or printing). I know the image will have different characteristics if I do that, and that's part of my exposure calculation. I can over expose and under-develop, and get more highlight compression and more shadow detail. I can under expose and overdevelop and get more contrast, more grain, but with the risk of blocked highlights. All from the same film stock.

I expose Red with very similar thinking, and that's where ISO has become important again -- not the camera's ISO setting, but ISO as a reference for light levels in front of the lens. I know that the sensor is about 320 ISO native, but I don't love the completely-clean image I get at 320 for most things. At 800, I get a bit of very pleasant noise, which I like, and the added benefit of some headroom that lets me roll the highlights off nicely. But for things like tabletop and package shots, I usually want a "fatter negative" with more color and a bit less noise, so I expose for 640 or 500, knowing I have to watch the highlights more carefully, but knowing that it will do things to the image that I want. Or as with Gunleik's image above, I can underexpose and get an image where darks cluster together and mix with noise a bit, and the hilights occupy most of the long slope of the tonal curve. All with a sensor that has a fixed response.

What I can't do is expect that a scene I "shoot at ISO 400" will look like a scene that I "shoot at ISO 3200". That won't happen. (And it won't happen with any other camera on the market either, by the way.) Light matters.

I'm going to copy and paste this into my reference notes because it spells out a plan of action that I might use... assuming these same numbers correlate to Dragon

Mark L. Pederson
02-12-2014, 11:19 AM
I want a flat logish style image shows me something more complete than linear light. RAW as it is or RC4/REDlog film would be perfect.

What is wrong with REDlogfilm right now? What do you want to see that you can't see in REDlogfilm ?



I want to see this so I have a sense of the total frame and I can later decide what I have in the blacks and the highlights so that I can adjust later in the grade, know what is blown out and what can not be recovered.
Only way to do this is false color meters - just like being discussed in Truth ... or False Color thread. This can not be indicted accurately enough by a single RGB representation alone.



I want the brightness of that image to be as close to the best possible image the camera can produce (sensor native 5000K, baseline ISO accurate to metered light, noiseless image) that yields the sharpest image with the best color fidelity and the widest latitude, without coloring it up for me. (If I want to deviate from that I will do my own testing and cook my own look, but as a start I want to know what the manufacture thinks will make the camera/film stock shine in terms of optimum technical precision, by adding a simple s-curve to make one lights easy.

How much for the goose Wonka :)

This is a pretty flawed request IMO because " best possible image" and " best color fidelity", etc. are SUBJECTIVE. You would need to articulate technically what you want to see - in technical terms - not subjective.



I want two monitoring paths, the professional one as above with menus, guides etc and a clean cooked look for clients.
You can do this now - just uncheck "tools" in the monitor setup. You gotta go one HDMI and one HDSDI - but you can convert HDMI to HDSDI with those bad ass small ATMOS converters.


I want histogram, goal posts and Exposure tools. No ire, no zebra or any of that crap leftover from shitty video cameras.

battistella

You have a histogram now. You don't need to use any of the IRE tools - but they can stay there for folks that like to use them.

Mark L. Pederson
02-12-2014, 11:24 AM
this goes to my point of RED taking a leadership position as the replacement of digital film. I feel they should be on this like a pit bull on a bone. Needs to be established right now, with this sensor and this system. Put the eggs in that basket.

You hear me on that one RED. :)



battistella

Well ... in all honesty David - most experienced cinematographers understand ISO on the RED, Alexa, F65, etc. and have no real issue with exposing on the sensor(s) and system.

I think it IS established with the sensor and system.

I just think there is a lot of confusion over ISO with folks who don't understand the basics - which is okay - it can and will be confusing if you never really understood the basics - but this forum exists, right? Reducation exists, right?

Scott Crawley
02-12-2014, 12:01 PM
Yes David, thank you. Those things all being about equal are understood.

For me the crux of it (Which Mark kindly clarified for me.) was this idea of adding gain to the signal coming off of the sensor... but we are not adding gain to the signal coming off of the sensor... at least not directly to the recorded image. We are recording the straight signal produced by the sensor, but adding gain in the monitoring path both during production and post. It may seem a fine distinction, but it is a key distinction. Granted it isn't something I think about every day, since I routinely expose to RAW view with an eye on RG3/RC3 only as a window into post processing. That way I don't get caught up in exposure errors due to poor ISO selection. Generally speaking I plan for a basic exposure that is correct and use that as a basis for any look that I am trying to create. The more creative or extreme the look the further I deviate from that plan but that is the basis of my process.

Incidentally, I frequently grade my own work and my procedure for that is generally the same.


Yes you are on track. But I'd modify a couple of these observations. The ISO setting on your Pentax changes the way your light meter responds, that's true. But it's important because it changes that way you will expose the film. And it very much changes that way the captured values are displayed (though not until after developing and printing).

To quote myself from another thread: After some detours, I've come to think about exposure on Red in much the same way that I used to think about it on film. A film has a fixed sensitivity (ISO), but knowing that, I can choose to expose at a different ISO and push or pull in post (either chemically or in transfer or printing). I know the image will have different characteristics if I do that, and that's part of my exposure calculation. I can over expose and under-develop, and get more highlight compression and more shadow detail. I can under expose and overdevelop and get more contrast, more grain, but with the risk of blocked highlights. All from the same film stock.

I expose Red with very similar thinking, and that's where ISO has become important again -- not the camera's ISO setting, but ISO as a reference for light levels in front of the lens. I know that the sensor is about 320 ISO native, but I don't love the completely-clean image I get at 320 for most things. At 800, I get a bit of very pleasant noise, which I like, and the added benefit of some headroom that lets me roll the highlights off nicely. But for things like tabletop and package shots, I usually want a "fatter negative" with more color and a bit less noise, so I expose for 640 or 500, knowing I have to watch the highlights more carefully, but knowing that it will do things to the image that I want. Or as with Gunleik's image above, I can underexpose and get an image where darks cluster together and mix with noise a bit, and the hilights occupy most of the long slope of the tonal curve. All with a sensor that has a fixed response.

What I can't do is expect that a scene I "shoot at ISO 400" will look like a scene that I "shoot at ISO 3200". That won't happen. (And it won't happen with any other camera on the market either, by the way.) Light matters.

D Fuller
02-12-2014, 12:08 PM
I'm going to copy and paste this into my reference notes because it spells out a plan of action that I might use... assuming these same numbers correlate to Dragon

The numbers might not correlate exactly, but the methodology will. For example, if the Dragon native ISO is 800, it would just shift the whole thing up the scale a bit. Very much like switching to a higher-speed film.

David Battistella
02-12-2014, 12:15 PM
How much for the goose Wonka :)

This is a pretty flawed request IMO because " best possible image" and " best color fidelity", etc. are SUBJECTIVE. You would need to articulate technically what you want to see - in technical terms - not subjective.
.

Mark

the technical responsibility is not mine, it's REDS responsibility.

Look ok at it like this. Red makes the camera and they make the film stock.

Actually, we hear a lot about the body form factor, etc. the way arri or Aaton would but we also hear about image, the way kodak or Fuji would. So let's say the red sensor is a film stock.

As as I stated, the same way kodak or Fuji provides an Asa value, for their film with a sticker on it that says 500asa daylight, they are telling us that with daylight sources at meters set to 500asa and exposing this film in that way and processing it with the correct chemistry will yield a correctly balanced image and in this way the stock will perform at or near its optimum.

Thats for for the beginer, it's a baseline.

The he expert says ok. What if I make this 2 stops over, cross process push, pull and find their own style and method.

But it a baseline exists.

In a sense red is handing us the dragon and saying (quoting Phil) the Asa rating of this film is 250-2000 rate it however you like. I just think the manufacturer of the sensor (like film) should determine through their own internal testing the baseline for the novice user. Like, here, 5600k sources, 640 Asa and set aperture and shutter accordingly and you'll get decent relatively noise free images.

Shoukd i and 5000 other users be telling them that? no. If they want people to get successful images out of their sensor , the way lkodak and Fuji would wanttheircustomers to experience, then you test and you determine what is a. Best starting point.

Otherwise se you'll get, I started at. 2000 and pushed it to 6400 and now it's really noisy all day here.

Its up to us to discuss and push the expert stuff once they lay the groundwork.

Battistella

D Fuller
02-12-2014, 12:19 PM
Well ... in all honesty David - most experienced cinematographers understand ISO on the RED, Alexa, F65, etc. and have no real issue with exposing on the sensor(s) and system.

I think it IS established with the sensor and system.

I just think there is a lot of confusion over ISO with folks who don't understand the basics - which is okay - it can and will be confusing if you never really understood the basics - but this forum exists, right? Reducation exists, right?

A lot of confusion comes from the fact that Red has these three different customer sets: people who learned on film, with its fixed ISO per film stock and workflow that includes post-processing; people who come from video, where ISO has no meaning at all, there is just gain; and the DSLR group, for whom ISO is a baked-in gain-with-noise-reduction setting. They all understand ISO differently, and I think we often talk past each other because we don't understand the terms in the same way.

Gunleik Groven
02-12-2014, 12:25 PM
A lot of confusion comes from the fact that Red has these three different customer sets: people who learned on film, with its fixed ISO per film stock and workflow that includes post-processing; people who come from video, where ISO has no meaning at all, there is just gain; and the DSLR group, for whom ISO is a baked-in gain-with-noise-reduction setting. They all understand ISO differently, and I think we often talk past each other because we don't understand the terms in the same way.

+ 112

And that is REDs strength and weakness.

Problem is when the film guys get "taught" by a videoguy to unlearn all that lovely knowledge. :)

Or when experienced TV guys start shooting RED

(both cases will work, but there is room for confusion)

Mark L. Pederson
02-12-2014, 12:27 PM
As as I stated, the same way kodak or Fuji provides an Asa value, for their film with a sticker on it that says 500asa daylight, they are telling us that with daylight sources at meters set to 500asa and exposing this film in that way and processing it with the correct chemistry will yield a correctly balanced image and in this way the stock will perform at or near its optimum.

Thats for for the beginer, it's a baseline.

The he expert says ok. What if I make this 2 stops over, cross process push, pull and find their own style and method.

But it a baseline exists.

In a sense red is handing us the dragon and saying (quoting Phil) the Asa rating of this film is 250-2000 rate it however you like. I just think the manufacturer of the sensor (like film) should determine through their own internal testing the baseline for the novice user. Like, here, 5600k sources, 640 Asa and set aperture and shutter accordingly and you'll get decent relatively noise free images.
Battistella

Well ... like I have said over and over - there is not really a NATIVE ISO. There is RANGE. If you want to pick ONE baseline - you really need to pick that based on your exposure method and subjective preference. If you are a novice - set the Dragon at 640 ISO and have a great time. You will shoot great images. Done.

But these cameras are not "point and shoot" cameras - they are very high end tools.

I'm just unclear based on your post - and it could be a language thing - exactly what you want RED to do that they are not doing right now?

Mark L. Pederson
02-12-2014, 12:32 PM
A lot of confusion comes from the fact that Red has these three different customer sets: people who learned on film, with its fixed ISO per film stock and workflow that includes post-processing; people who come from video, where ISO has no meaning at all, there is just gain; and the DSLR group, for whom ISO is a baked-in gain-with-noise-reduction setting. They all understand ISO differently, and I think we often talk past each other because we don't understand the terms in the same way.

Agreed.

The answers, IMO, are ALL in the roots of shooting film.

Still or Motion - but FILM.

RAW is digital FILM.

If you understand the fundamentals of shooting and exposing FILM you are all good with RAW.

RED cameras are digital motion picture cameras. They do not actually shoot "video". And the EPIC is not DSLR camera.

David Battistella
02-12-2014, 12:35 PM
Mark,

Are you saying ISO 640 is a base rating or is Red saying that ?


Battistella

Will Keir
02-12-2014, 12:37 PM
A variable film stock.



I have had and seen the best results when people treat RED as a FILM STOCK and light accordingly.

If Dragon actually can be rated 250-2500ISO with no penalty then we have the digital equivellent of every film stock ever made and that would be a minor miracle.

Battistella

Robert Horwell
02-12-2014, 12:40 PM
You should lower the ISO to allow more light into the sensor. More light = cleaner image. I like 640-800 as a "base" ISO on Dragon for interiors, etc. - 1280 for night ext. - 320 for bright daylight - really depends on what you are trying to do. Shooting 320 on Dragon is TOTALLY different than shooting 320 on MX.

Mark can you please expand your reasoning and methodology of dropping the iso in ext daylight on dragon.? On MX i would push the iso in order to push my middle grey further up the EI and grab a couple more stops at the top end.

many thanks.

Gunleik Groven
02-12-2014, 12:41 PM
And the EPIC is not DSLR camera.

Ouch... ;)

http://static9.oneclick.gunleik.com/2014/02/b3605b40ebd12d3dfa6f24be282470a9a13da49e.jpg

Elsie N
02-12-2014, 12:42 PM
Well ... set the Dragon at 640 ISO and have a great time. You will shoot great images. Done.

But these cameras are not "point and shoot" cameras - they are very high end tools.
...

True these cameras are high end tools but... by your own words setting the Dragon to an assigned native ISO and using that as your exposure method, shooting doesn't have to be a complicated headache. That's the beauty of RED cameras... you can do precision or you can do a full choke scattergun. And sometimes an audience cannot tell the difference. '-)

Mark L. Pederson
02-12-2014, 12:42 PM
Ouch... ;)



Because it's much MORE and it ain't no single lens reflex camera.

D Fuller
02-12-2014, 12:43 PM
Agreed.

The answers, IMO, are ALL in the roots of shooting film.

Still or Motion - but FILM.

RAW is digital FILM.

If you understand the fundamentals of shooting and exposing FILM you are all good with RAW.

RED cameras are digital motion picture cameras. They do not actually shoot "video". And the EPIC is not DSLR camera.

That's all true. But an awful lot of people don't understand that at all, and many have no experience of film to draw on. And for me, with a lot of years of experience of film, it took a while to realize that. I thought digital cinema was "something different". And I suppose it is. But it's a lot less different that it is the same when it comes to the craft of photography.

Gunleik Groven
02-12-2014, 12:45 PM
Because it's much MORE and it ain't no single lens reflex camera.

Hahahaha

I know. Just had to! :)

And this was Dragon...

Mark L. Pederson
02-12-2014, 12:45 PM
True these cameras are high end tools but... by your own words setting the Dragon to an assigned native ISO and using that as your exposure method, shooting doesn't have to be a complicated headache when shooting. That's the beauty of RED cameras... you can do precision or you can do a full choke scattergun. And sometimes an audience cannot tell the difference. '-)

Yes. Yes. Yes.

You certainly can use it without leveraging all the power. And it's NOT hard. And YES that is the beauty of RED cameras.

But - since we have a REDUSER forum - why not push for the advanced class.

Mark L. Pederson
02-12-2014, 12:46 PM
That's all true. But an awful lot of people don't understand that at all, and many have no experience of film to draw on. And for me, with a lot of years of experience of film, it took a while to realize that. I thought digital cinema was "something different". And I suppose it is. But it's a lot less different that it is the same when it comes to the craft of photography.

POST OF THE DECADE.

It's so much about the craft of photography and the fundamentals of film.

Gunleik Groven
02-12-2014, 12:50 PM
That's all true. But an awful lot of people don't understand that at all, and many have no experience of film to draw on. And for me, with a lot of years of experience of film, it took a while to realize that. I thought digital cinema was "something different". And I suppose it is. But it's a lot less different that it is the same when it comes to the craft of photography.

And that is exactly what I have seen a number of times... Experienced cinematographers throwing out their decades of knowledge, because there is no OVF... simply put.

And then having to "guide them back home".

Which is kinda ironical, as I am a digital dude... :)

Elsie N
02-12-2014, 12:50 PM
Yes. Yes. Yes.

You certainly can use it without leveraging all the power. And it's NOT hard. And YES that is the beauty of RED cameras.

But - since we have a REDUSER forum - why not push for the advanced class.

You're right... advanced class is what this is and a very informative one at that. But I just want to mention to those who may be overwhelmed by the different styles and viewpoints expressed here that there is a backup plan called post. '-)

Gunleik Groven
02-12-2014, 12:51 PM
One thing that I think may get "lost" in this advanced class, is that Mark, David Fuller and I pretty much advocate simplicity.

The "advanced" thing lays in understanding simplicity... :)

Mark L. Pederson
02-12-2014, 12:55 PM
Are you saying ISO 640 is a base rating or is Red saying that ?


Battistella

I'm saying ...

THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING

There's a RANGE.

If you forced me to choose one ISO to shoot everything on a Dragon - I would choose 640. RED doesn't say there is a "base rating". They have to choose one ISO to have the camera default to something. They choose 800. I do not know what their exact logic and path is to choosing that - and Dragon at ISO 1280 is equal to - or better than MX at 800 with respect to noise when scaling to 2K for sure - but - I love Dragon images that are super clean - I like lower ISOs more and more. But ... it's a subjective thing.

But I do not believe in a "base ISO" - I believe that a DP should shoot tests with the camera based on all the info out there - and test with his/her exposure method - for his/her subjective choices for the project. But I do tell people it is my OPINION that 640 is the sugar.

If I shot a horror movie on Dragon - I'd choose 2 or 3 ISOs to live on - and they would be totally different that the 2 ISO's I'd choose for a romantic comedy. But that's just me. It's not right or wrong. Subjective choice.

I personally would not shoot a whole feature on one ISO. You certainly can - and MANY people do. But I wouldn't.

D Fuller
02-12-2014, 12:59 PM
One thing that I think may get "lost" in this advanced class, is that Mark, David Fuller and I pretty much advocate simplicity.

The "advanced" thing lays in understanding simplicity... :)

exactly!

Mark L. Pederson
02-12-2014, 01:01 PM
One thing that I think may get "lost" in this advanced class, is that Mark, David Fuller and I pretty much advocate simplicity.

The "advanced" thing lays in understanding simplicity... :)

2nd Post of Decade. This must be a good thread :)

Will Keir
02-12-2014, 01:01 PM
Mark,

I'm putting the energy into this because it's something I teach people who use our camera quite often. I encourage you to teach the basics, reinforce the fundamental principals of the RED camera systems. A well presented "sticky" on the subject would help a lot of people educate themselves on some best practices when exposing the RED cameras. I know you are putting a ton of energy into teaching and this knowledge represents a significant investment on your part, so let's come together and find the best possible way we can to educate our friends, peers and colleagues. All the best to you.

I re-read the post several times, it's presented in a difficult way, misleading at best even in context. Let's let this one rest and continue to explain and educate the best we can. You have a lot to offer Mark, we appreciate your time and efforts.


Will - you are taking me out of context - when I said "You should lower the ISO to allow more light into the sensor. More light = cleaner image." I was SPECIFICALLY responding to a question a user posted where he asked if he should leave ISO at 2000 and then limit the light with NDs vs lowering the ISO. You should re-read that post. I guess I should have said "You should lower the ISO vs. keeping at 2000 and adding ND filters as to allow more light into the sensor. More light = cleaner image." - but the guys question was quoted in my response.

Will Keir
02-12-2014, 01:02 PM
This should be part of a sticky. :)



35mm motion picture film - it has an ISO rating on the can. Let's say it's 500. That's a recommended ISO. That number does NOT effect how much light goes into the motion picture film camera. Only aperture, filters and shutter do (sound familiar). It's a recommendation for how a DP and/or Gaffer should set his/her light meter as to measure light to set an exposure - aka exposure method.

Now, some DPs would rate that same film stock at 640 - some at 320 - and by changing the rating - changing the ISO - no more or less light came into the camera - it's just a setting on the light meter ...

D Fuller
02-12-2014, 01:03 PM
A variable film stock.

No. A film stock you can expose and develop variably. (But there will be differences in the image when you do.)

Scott Crawley
02-12-2014, 01:04 PM
I don't see how what you and David are saying are at odds with one another. Everything in this quoted post is also true of film. Film manufacturers assign each stock an optimal ISO, so does Red.

The response curve of each is a slope, not a point, so both imaging methods can be used over a range of values, but each has a subjective sweet spot. Film manufacturers defined a target ISO where they feel their stocks responded best across the range, and Red does the same. Red is just not as committed to a value.

David seems to be saying, and I also suggested that Red go ahead and choose a value for the sensor and not be quite so vague about it. Doing so doesn't dumb things down or limit the educated shooter's ability to push and pull and work all around that ISO as they see fit. It does however provide a foundation for all.

I'm not sure why anyone would resist that.



Well ... like I have said over and over - there is not really a NATIVE ISO. There is RANGE. If you want to pick ONE baseline - you really need to pick that based on your exposure method and subjective preference. If you are a novice - set the Dragon at 640 ISO and have a great time. You will shoot great images. Done.

But these cameras are not "point and shoot" cameras - they are very high end tools.

I'm just unclear based on your post - and it could be a language thing - exactly what you want RED to do that they are not doing right now?

Will Keir
02-12-2014, 01:07 PM
Yes. Even though it seems the use of light meters is fading away with the WYSIWYG generation, we are in a time of change across the board. We might see a future where the light meter is irrelevant, even archaic.



It was their job to understand ISO and rating the light meter - and how THEIR EXPOSURE METHOD (using a light meter) created results on a GIVEN FILM STOCK.

MX is a film stock.

DRAGON is a film stock.

The last Reducation class I taught I asked the class to raise their hands if they understood what Contrast Ratio meant. One person raised their hand and had the wrong answer. I believe that the DSL and digital camera movement has pushed the "point and shoot" and "WYSIWYG" thing so much ... the newer generations are sadly missing the most fundamental basics of cinematography/photography.

David Battistella
02-12-2014, 01:09 PM
I don't know what is wrong with my english and my comprehension and logic is pretty good.

if we are going to treat a dragon sensor like film then let's do that.

there is no base ISO on a 500asa film can either. I can say there is a range, but that range involves compromise.

When kodak presented a new film stock all of these variables were in play, but they told you what they felt the most color accurate, technically correct, noise free image you could get from the stock. They internally tested it and presented recommendations for acquisition and post.

So that is all I'm saying RED (the manufacturer) could say for noise free, wide dr images, most accurate color representation and in optimal situations we think you should rate this digital film stock at:

1. Rate Asa/ISO xxx
2. color temperature xxx

Of course there is a range. It means deviating from the optimal image forces you to think as a cinematographer.


Is my english really that incomprehensible? Because as I read your post we are saying the exact same thing 95% of the time.


Battistella

Will Keir
02-12-2014, 01:12 PM
I LOVE this advise.


You need to know your shit. You need to know the fundamentals. If it is confusing to you - keep asking - read books - seek out a mentor - get a shitty job under an expert and then pay attention to every single thing he or she does.

Elsie N
02-12-2014, 01:12 PM
I don't know what is wrong with my english and my comprehension and logic is pretty good.

if we are going to treat a dragon sensor like film then let's do that.

there is no base ISO on a 500asa film can either. I can say there is a range, but that range involves compromise.

When kodak presented a new film stock all of these variables were in play, but they told you what they felt the most color accurate, technically correct, noise free image you could get from the stock. They internally tested it and presented recommendations for acquisition and post.

So that is all I'm saying RED (the manufacturer) could say for noise free, wide dr images, most accurate color representation and in optimal situations we think you should rate this digital film stock at:

1. Rate Asa/ISO xxx
2. color temperature xxx

Of course there is a range. It means deviating from the optimal image forces you to think as a cinematographer.


Is my english really that incomprehensible? Because as I read your post we are saying the exact same thing 95% of the time.


Battistella

David, they may not be able to do that yet... with the tweaking of the new OLPF and Graeme's unfinished Dragon Color symphony.

Will Keir
02-12-2014, 01:15 PM
Yes Scott. ISO and FLUT control the same function, where middle grey is set. FLUT uses smaller increments to do this while ISO change are more significant.


The ISO control and the FLUT control are the exact same adjustment, are they not?

David Battistella
02-12-2014, 01:16 PM
Yes. Even though it seems the use of light meters is fading away with the WYSIWYG generation, we are in a time of change across the board. We might see a future where the light meter is irrelevant, even archaic.


But you have to understand the subtle things that move away from perfect as you move toward rating differently, colors wash out, skin tone can start to deteriorate, noise is introduced, highlights clips at a different value, the amoun of room you have in highlights an blacks varies and the general DR range shifts.

we should have an idea from the manufacturer what they consider optimal, because any digital sensor or films characteristic changes depending on how much and what kind of light hits it and how each individual controls that light.

the red M Loved daylight and a lot of it.
The Mx loves daylight but got better with tungsten.

this is probably why there were always skin tone problems, because you can't just fly around the scale and expect the perfect output. The correct/optimal amount of light on the sensor matters and that should not be entirely up to users to determine.

Battistella

Scott Crawley
02-12-2014, 01:17 PM
David, they may not be able to do that yet... with the tweaking of the new OLPF and Graeme's unfinished Dragon Color symphony.

That is true of Dragon but not the MX, or M, but Red resisted labeling them too.

Perhaps it was because up to this point digital imaging was not equal to film and Red wanted to avoid the direct comparisons that the labels David is suggesting would have promoted.

It's just a brain fart of a theory, but it's a theory.

David Battistella
02-12-2014, 01:17 PM
Thanks Scott,

you have interpreted my posts well.

Battistella


I don't see how what you and David are saying are at odds with one another. Everything in this quoted post is also true of film. Film manufacturers assign each stock an optimal ISO, so does Red.

The response curve of each is a slope, not a point, so both imaging methods can be used over a range of values, but each has a subjective sweet spot. Film manufacturers defined a target ISO where they feel their stocks responded best across the range, and Red does the same. Red is just not as committed to a value.

David seems to be saying, and I also suggested that Red go ahead and choose a value for the sensor and not be quite so vague about it. Doing so doesn't dumb things down or limit the educated shooter's ability to push and pull and work all around that ISO as they see fit. It does however provide a foundation for all.

I'm not sure why anyone would resist that.

D Fuller
02-12-2014, 01:19 PM
But you have to understand the subtle things that move away from perfect as you move toward rating differently, ...


Or toward perfect, depending on your intent. :-)

Elsie N
02-12-2014, 01:21 PM
That is true of Dragon but not the MX, or M, but Red resisted labeling them too.

Perhaps it was because up to this point digital imaging was not equal to film and Red wanted to avoid the direct comparisons that the labels David is suggesting would have promoted.

It's just a brain fart of a theory, but it's a theory.
Then this request should have been debated years ago at the beginning rather than now when we are moving into a new realm.

(Apoligies, I think in Dragon terms now'-)

David Battistella
02-12-2014, 01:24 PM
David, they may not be able to do that yet... with the tweaking of the new OLPF and Graeme's unfinished Dragon Color symphony.

So true, but it is precisely this vague sort of stuff that launches a wave of speculation and conjecture. When do you do it? When there 500 cameras out there? 1000? And some stuff is dynamite and other stuff is, meh?

what happened to wanting to release finished stuff? Phil Holland's new OLPF post is amazing, amazing stuff, we can really see how powerful this combo is going to be. But I think we should be hearing from red officially on this soon, probably by NAB.

battistella

Scott Crawley
02-12-2014, 01:24 PM
Then this request should have been debated years ago at the beginning rather than now when we are moving into a new realm.

(Apoligies, I think in Dragon terms now'-)

But Dragon MAY represent a turning point, a point where Red is confident enough to assert that it is now indeed comparable to film. If these theories are correct then there may be no reasons left NOT to openly label and treat a sensor in the same manner as film stocks.

Mark L. Pederson
02-12-2014, 01:26 PM
David seems to be saying, and I also suggested that Red go ahead and choose a value for the sensor and not be quite so vague about it. Doing so doesn't dumb things down or limit the educated shooter's ability to push and pull and work all around that ISO as they see fit. It does however provide a foundation for all.

I'm not sure why anyone would resist that.

What other cameras do this?

Gunleik Groven
02-12-2014, 01:27 PM
Then this request should have been debated years ago at the beginning rather than now when we are moving into a new realm.

(Apoligies, I think in Dragon terms now'-)

It was...

Both the raw-metering and these issues were heavily debated in the early days... :)

Scott Crawley
02-12-2014, 01:27 PM
What other cameras do this?

What does it matter?

Again- Red already does it. They just are not loud or clear about it, so we end up explaining it ad nauseum and some of us get it wrong... Then people get confused, you get annoyed... :-)

David Battistella
02-12-2014, 01:30 PM
Or toward perfect, depending on your intent. :-)

Absolutely. It's all subjective in the end, but kodak is an image science company as is RED, and that scientific part of cinematography is a part of the art. Like all great art (and I live in the city of the renaissance and live it every day) the masters were all formally trained apprentices who had very solid fundamentals in science. Perhaps I could have used the word beauty, ultimately perfect is...well, when it just all works and no words need to be exchanged, it can't be talked about, but has to be experienced.

Still, science drives all of this stuff and it's not geeky to include art and science, they hold hands, they are lovers.

battistella

D Fuller
02-12-2014, 01:32 PM
POST OF THE DECADE.

It's so much about the craft of photography and the fundamentals of film.

Aw, shucks. :)

Mark, can i just say that you've started a string of threads lately that are some of the most useful and insightful I've seen on Reduser in a long time. It's so good to see threads that really dive into the craft.

EDIT: I don't want to fail to recognize the contributions of everyone else who has been contributing here. Thanks to all for the discussion.

Elsie N
02-12-2014, 01:33 PM
But Dragon MAY represent a turning point, a point where Red is confident enough to assert that it is now indeed comparable to film. If these theories are correct then there may be no reasons left NOT to openly label and treat a sensor in the same manner as film stocks.

I gotta go with Mark, Gunleik, David Fuller, et al... thinking of it as a range helps one (me) understand that changing the ISO changes the way you choose to expose. If we need one to hang our hats on, do our own tests or haunt this forum for what the ones who test (at the expense of their own time) come up with for their method of shooting. I'm not sure RED can determine a "best practices" ISO because that term can apply anywhere up and down the range, depending on the individual. Not having them label "Individual" for us is a plus, now that I better understand what's going on.

Scott Crawley
02-12-2014, 01:33 PM
Aw, shucks. :)

Mark, can i just say that you've started a string of threads lately that are some of the most useful and insightful I've seen on Reduser in a long time. It's so good to see threads that really dive into the craft.


+1.

Thanks Mark

David Battistella
02-12-2014, 01:35 PM
What other cameras do this?

The question is

what other film stocks do this?

because I am saying that the digital sensor is the film (kodak, Fuji whatever) and the camera is the just the body a 435.

A dragon is the 435 and it also is the kodak film stock and that distinction needs to be made. Because red is not just a camera company, red has Graeme and that is the "kodak image science part" of RED. And make no mistake, red is an image science company.

Battistella

D Fuller
02-12-2014, 01:36 PM
Still, science drives all of this stuff and it's not geeky to include art and science, they hold hands, they are lovers.

battistella

I love this.

Scott Crawley
02-12-2014, 01:36 PM
... Not having them label "Individual" for us is a plus, now that I better understand what's going on.

That is to your credit. :-) keep learning.

And BTW I don't disagree with any of those folks either.

David Battistella
02-12-2014, 01:38 PM
. I'm not sure RED can determine a "best practices" ISO because that term can apply anywhere up and down the range, depending on the individual. Not having them label "Individual" for us is a plus, now that I better understand what's going on.

Not true. There will be a sweet spot and many people will default to that. It will be discovered, I just think red should be leading that race.


Battistella

Gunleik Groven
02-12-2014, 01:40 PM
There are a few issues with "recommended ISO"

On the MX, it could have been 320 for daylight balanced situations. But that already gets confusing, because very few have any idea of how white-balanced occurs, so 800 was a good general advice to leave headroom for WB operations to be not too destructive.
Still you could get excellent results, depending on where you wanted to go, lighting for 320 or 1600. It would look different. Noise would be different. But generally "if it looked good at 800, you would have a pretty safe image under most WB situations".

Now... If Fincher shoots a wonderful piece at 3200... :) Would that be a good advice? :)

The Dragon has a wider "generally acceptable range".

My philosophy has been to stick to one camera-setting (but I do not really advocate that).
Reason for that being that I learn to pick up image-cues in that image as to what will become post-issues or not. Probably I will land on pretty much the same approach on Dragon, I am just not done yet in deciding. I think Marks 640 sounds like a likely sweetspot.

That fits well with what I saw that the RAW view was calibrated as earlier today.

IMHO, post on Epic is pretty simple.

Start off from a 640 RLF/5600 image and you are good for 90% of the shots I have seen. (probably even for that Fincher piece I described)

it is possibly not IDEAL for all those shots, but it is pretty close.

The last bit is the hard bit.

But it is really simple to get a really good result, with good colorists involved. :)

Dragon will be even more allowing.

Problem with discussions like these, it that they make some people think easy things are hard, while as I said, as I understand it, we really advocate simplicity in very intricate ways...

Advocating a more specific "sweet spot" would pretty much be advocating a "look".

I like that they do not do that!
But that is just me I guess.

One could also determine a spot with what gives x+/x- as a technical midpoint from something like the CML test I was just involved with.

I am not saying that is wrong. It is after all possible.

But it depends a bit on tolerance where you would put that spot.

I have a hunch David B and I might have chosen a different spot. And I think that is good... :)

Mark L. Pederson
02-12-2014, 01:41 PM
+1.

Thanks Mark

You are all gonna start to get sick of me soon enough when I blow up a new CDL / 3D LUT thread I'm gonna drop this weekend :)

David Battistella
02-12-2014, 01:43 PM
I'm all for simplicity and simplifying. :)

Mark L. Pederson
02-12-2014, 01:43 PM
thinking of it as a range helps one (me) understand that changing the ISO changes the way you choose to expose. If we need one to hang our hats on, do our own tests or haunt this forum for what the ones who test (at the expense of their own time) come up with for their method of shooting. I'm not sure RED can determine a "best practices" ISO because that term can apply anywhere up and down the range, depending on the individual. Not having them label "Individual" for us is a plus, now that I better understand what's going on.

Yes. Yes. Yes.

David Battistella
02-12-2014, 01:43 PM
You are all gonna start to get sick of me soon enough when I blow up a new CDL / 3D LUT thread I'm gonna drop this weekend :)


Im not not going near that one. :) LOL

Scott Crawley
02-12-2014, 01:44 PM
You are all gonna start to get sick of me soon enough when I blow up a new CDL / 3D LUT thread I'm gonna drop this weekend :)

:lurk5:

Gunleik Groven
02-12-2014, 01:44 PM
You are all gonna start to get sick of me soon enough when I blow up a new CDL / 3D LUT thread I'm gonna drop this weekend :)



LOOOOOL


I am soooooooooooo glad to have you back here Mark, you cannot imagine! :)

But THAT thread, I guess I will just watch! :)

Mark L. Pederson
02-12-2014, 01:46 PM
Advocating a more specific "sweet spot" would pretty much be advocating a "look".

BOOM. Thank you Gunleik - I was trying so damn hard to figure out how to say this - and you nailed it.

But for anyone who just can't wrap their heads around the reason and advantages to shoot different ISOs - well ... put that Dragon on ISO 640 and go tear it up :)

D Fuller
02-12-2014, 01:46 PM
That'll draw a whole different crowd. LOL!

But it ll be interesting, I'm sure.


You are all gonna start to get sick of me soon enough when I blow up a new CDL / 3D LUT thread I'm gonna drop this weekend :)

Elsie N
02-12-2014, 01:52 PM
Not true. There will be a sweet spot and many people will default to that. It will be discovered, I just think red should be leading that race.


Battistella
While I generally like the idea of a default sweet spot, setting one becomes an "average" setting. But if they reveal that setting, I think it should be accompanied by disclaimers as to lighting, aperture setting... maybe even brand of lens used. Talk about your slippery slopes.

Mark L. Pederson
02-12-2014, 01:52 PM
That'll draw a whole different crowd. LOL!

But it ll be interesting, I'm sure.

Well ... RED needs to implement ASAP - and I want to try to cheer them on and try to demonstrate that it will NOT be hard for them to do it - and try to prove that it will be a massive benefit.

Will Keir
02-12-2014, 01:55 PM
This has been a good conversation. We've created some good information to fly around...

I for one, need to spend some quality time around those that came before me, with light meters and variable situations, to appreciate the tools we have now, and how far we've come.

While some consider film old history, it's principals for exposing photography are longer lasting and before you break the rules, learn em.

David Battistella
02-12-2014, 01:55 PM
Dragon, the nihilistic exposure experience.

Treat it however you want, it doesn't matter! LOL. :)


battistella

Scott Crawley
02-12-2014, 01:56 PM
While I generally like the idea of a default sweet spot, setting one becomes an "average" setting. But if they reveal that setting, I think it should be accompanied by disclaimers as to lighting, aperture setting... maybe even brand of lens used. Talk about your slippery slopes.Nonsense. (No offense intended.) How many times did Red say (And I am paraphrasing) We recommend shooting the MX @800 ISO. Hell that was practically the first thing they said about it when it was released.Edit: and nobody fell off of that slope. ;-)

They really drove the 800 point home with videos like this one:

http://www.red.com/learn/interviews/greg-st-johns-epic-transition

We need another Schilowitz, if that is possible.

D Fuller
02-12-2014, 01:56 PM
Well ... RED needs to implement ASAP - and I want to try to cheer them on and try to demonstrate that it will NOT be hard for them to do it - and try to prove that it will be a massive benefit.

It's something I know nothing about. And for my work, i'm not sure whether I need it or not, but knowing more is always better.

Mark L. Pederson
02-12-2014, 01:57 PM
But THAT thread, I guess I will just watch! :)

Bullshit. You are Mr. Signalchain - CDL & 3D LUT workflows are all about signalchain. You will have to join the party if I'm throwin' it -

Gunleik Groven
02-12-2014, 02:10 PM
Bullshit. You are Mr. Signalchain - CDL & 3D LUT workflows are all about signalchain. You will have to join the party if I'm throwin' it -

Guess I will have to buy beer and popcorn... :)

David Battistella
02-12-2014, 02:26 PM
I'm going to start calling Gunleik, Mark and Phil

THE MOD SQUAD

very tight knit group with a mission.

Battistella

Bill Anderson
02-12-2014, 02:50 PM
Man, we have it good today, when using film there were so many variable to be tested and accounted for in order to establish repeatable and accurate results - it seemed never ending at time: No two meters agreed, no two camera shutters were the same, iso had to be established for every camera and meter and lens combo - chemical constituents varied, water temp and PH variables, agitation methods, chemical exhaustion rates, film emulsion batch variables, it seemed if you cocked your hat the wrong way it would all go to shit; and yet these demands tuned one up to such a fine degree we could nail it every time - had to, it was sink or swim. ( :

Elsie N
02-12-2014, 02:56 PM
Nonsense. (No offense intended.) How many times did Red say (And I am paraphrasing) We recommend shooting the MX @800 ISO. Hell that was practically the first thing they said about it when it was released.Edit: and nobody fell off of that slope. ;-)

They really drove the 800 point home with videos like this one:

http://www.red.com/learn/interviews/greg-st-johns-epic-transition

We need another Schilowitz, if that is possible.

IIRC, Jim may have initially been the one who suggested that number. And I don't remember him saying that was a hard number but merely the one he shoots. Maybe Jarred could post his preferred number and ask (if he is on site) or call Jim and ask him what his Dragon ISO sweet spot number is. If it's good enough for Jim, it's good enough for me (maybe '-).

But just like Mark said he prefers shooting 640 on Dragon, he also said that 1200, again IIRC, would correlate to MX's 800. That's a pretty large span.

Mark L. Pederson
02-12-2014, 03:08 PM
Man, we have it good today, when using film there were so many variable to be tested and accounted for in order to establish repeatable and accurate results - it seemed never ending at time: No two meters agreed, no two camera shutters were the same, iso had to be established for every camera and meter and lens combo - chemical constituents varied, water temp and PH variables, agitation methods, chemical exhaustion rates, film emulsion batch variables, it seemed if you cocked your hat the wrong way it would all go to shit; and yet these demands tuned one up to such a fine degree we could nail it every time - had to, it was sink or swim. ( :

Not to mention that freekin' MoviCam Compact with the mags that always seemed to jam at the worst time. I hated that damn camera.

Patrick Tresch
02-12-2014, 03:52 PM
Hello,

I was shooting Dragon today and I was thinking it would be great if RED would implement a new monitoring path : REDCOLOR+/GAMMA+

+ would be something like a better lowlight curve crushing less the blacks in favor of a gamma bump and a stronger denoise in the HMDI/HDSDI/LCD outputs of the camera.
This is to obtain a similar result to what we can achieve in RCX with a full debayer, Denoise set to 6 and a slight curve (what other manufacturers do in their debayered signal).

This would conduct in a less conservative iso setting (usually done to protect from noise) to bump a bit more the shadows (where the Dragon perfrom incredibly well), and this would also naturally push the DP to keep more DR in the highlights.

The traffic lights are hard to clip, or do show clipping after the highlights "color rendition" is lost or diminished. You don't clip but you can't get them out of the "Roll off zone" where they blend gently into white and use them as part of the picture.

What do you think? Too risky?


Pat

Mark L. Pederson
02-12-2014, 03:59 PM
Hello,

I was shooting Dragon today and I was thinking it would be great if RED would implement a new monitoring path : REDCOLOR+/GAMMA+

+ would be something like a better lowlight curve crushing less the blacks in favor of a gamma bump and a stronger denoise in the HMDI/HDSDI/LCD outputs of the camera.
This is to obtain a similar result to what we can achieve in RCX with a full debayer, Denoise set to 6 and a slight curve (what other manufacturers do in their debayered signal).

This would conduct in a less conservative iso setting (usually done to protect from noise) to bump a bit more the shadows (where the Dragon perfrom incredibly well), and this would also naturally push the DP to keep more DR in the highlights.

The traffic lights are hard to clip, or do show clipping after the highlights "color rendition" is lost or diminished. You don't clip but you can't get them out of the "Roll off zone" where they blend gently into white and use them as part of the picture.

What do you think? Too risky?


Pat

Sounds messy to me. Remember - you can alter parameters in the camera which non-destructively change the monitor path.

FLUT can be handy to adjust on camera if you have a "monitor happy" DP who tends to under expose :) I have done that trick more than a few times :) You can also make and load curves in camera.

Adrian Jebef
02-12-2014, 04:05 PM
Well ... like I have said over and over - there is not really a NATIVE ISO.


I'm saying ...

THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING THERE IS NO BASE RATING




Phil disagrees with you...






Or in a graphical explanation:


http://www.artbyphil.com/temp/redDragonGraphics/phfx_redDragon_ISOFLUTEmulation.png





I think the inquiring minds on this thread are searching for the holy grail of RED; what Phil refers to here as "Optimal Exposure is found near the Native ISO of the sensor"


Hmmm. So... what is the Native ISO of DRAGON? 2000? 640? There's a Stop and a Half difference between the two. Or, in real-world terms, blown highlights or noisy blacks.

Patrick Tresch
02-12-2014, 04:05 PM
Sounds messy to me. Remember - you can alter parameters in the camera which non-destructively change the monitor path.

FLUT can be handy to adjust on camera if you have a "monitor happy" DP who tends to under expose :) I have done that trick more than a few times :) You can also make and load curves in camera.

Curves&Flut are good but denoise as seen in RCX and some Graeme Magic to unleash the -5 to -8.5 stops still present in the Dragon RAW files is another story. That signal could also be recorded on the HDSDI feed, giving those Prores/DNXHD happy people the best proxies files possible "out of the camera".

Pat

Mark L. Pederson
02-12-2014, 04:10 PM
Phil disagrees with you...


Does he really?

Yo Phil ... what's the native ISO of the Dragon?

Blair S. Paulsen
02-12-2014, 04:34 PM
IMO RED put the "default" ISO for MX at 800 so people would be less likely to clip. This could be described as using the "alternate monitor brightness control" like a railing a few feet back from the scenic view to help keep people from falling over the side. I also buy the notion that they wanted enough leeway to facilitate channel balancing across a wide range of color temperatures - in part to compensate for the native response of CMOS sensors, as well as redistribution of Bayer CFA data that is inherently 50% green/25% blue/25% red.

Since multiple tests have shown that the Dragon is better in the highlights with a smoother transition into the clip than M or MX it could be argued that RED no longer needs to use a conservative "default" ISO biased to influence exposure choices down the scale a bit. Based on this theory, plus notes from Mark and others, I plan to use 640 as my preferred starting point - but its only a starting point. Full stop.

IAC, the issue of people mis-undersatnding the impact (or lack of same) of the ISO setting on what is written into the RAW data set has not helped RED's rep - fair or not. Many cameras have gain stages (usually analog) that actually boost the signal being captured and likely add noise reduction in proportion to the push. Since this processing step happens internally, many shooters rely on what the monitor is telling them and don't know or care what happened upstream. On RED, the metadata modulated version of the image shown on the monitor (and some tools) is essentially just a peek at one particular way of "developing" the RAW data set into a RGB picture at a particular reference ISO.

So if the RAW data set is set (code values fixed) - AND - the RGB monitor image derived from it is a sample characterization of that data set per settings, the real question might be how to best give useful feedback. My personal preference is to keep ISO and WB (3200 or 5600 only) the same every day so when I make changes in lighting or exposure those changes track the way my eye expects them to - I find lots of ISO changes too confusing.

I used to use the RAW view quite a bit but rarely look at it anymore, as, hold on to your hats, the only images anyone will ever see are RGB derived ones. That said, having a tool like EXPOSURE CHECK that is tied directly to sensor voltages and displayed in the most useful way possible (gamma encoding designed for the application) is nice to have available. If you want an absolute reading of the linear light values, I suggest you follow the advice of several posters and test thoroughly. In the field I just want a simple "check", as the name implies.

As others have noted, testing is the crux of the biscuit for realizing the full potential of any imaging device/signal chain.

Cheers - #19

Adrian Jebef
02-12-2014, 04:49 PM
BTW: I like Phil's graph but I believe it's a bit misleading in the way it shows "expanded" or "compressed" highlight/shadow with respect to the -2 and +2 stops of exposure. Looking at it, the graph seems to suggest that by opening or closing your exposure +/-2 Stops or changing your ISO you keep the same Dynamic Range end points but squeeze in or squeeze out more or less highlight/shadow detail. This is not how digital CMOS-based sensors work. They have a linear sensitivity to light unlike a film stock whose sensitivity is logarithmic. Scene exposure values become discretely coded into a digital camera's DR (ie: 0-1023 in a 10-bit scale), they do not bend or curve like film does. Technically, there is no knee or shoulder with a digital cinema camera. The exposure curve (gamma) is interpreted directly from the captured linear code values. Though the curve can be interpreted numerous ways via post transforms it has no bearing on the top and bottom end of scene exposure.

I prefer this graph on the relationship of a sensor's native Dynamic Range and ISO changes:


http://www.arri.com/mobile/apg/images/overview/exposure_index.jpg

Mark L. Pederson
02-12-2014, 05:07 PM
I for one, need to spend some quality time around those that came before me, with light meters and variable situations, to appreciate the tools we have now, and how far we've come.


You are a wise man Will.

watch this video -


http://youtu.be/k8ThmLwRs3g

Phil Holland
02-12-2014, 05:11 PM
Phil disagrees with you...


Does he really?

Yo Phil ... what's the native ISO of the Dragon?


Heh. There is no real "Native ISO". The cake is a lie. There is such a thing as base sensor sensitivity however and that's not what we're looking for though it's extremely important.

Before I continue, everybody real quick read this:
http://www.red.com/learn/red-101/iso-speed-revisited

i'm explaining ISO the way Red is explaining it.


What many of us refer to as Native ISO is the balancing point and even distribution of dynamic range above and below the midtone (most measure it off of 18% Gray), though not the way most would likely desire to shoot. Meaning the approximate middle ISO rating.

It's actually a horrible term and I should remove it from this graphic and change it to Base ISO.

However, I'll stir the pot as I just read the tonal placement on the new calibration and new OLPF.

Get ready. I'm going to reveal the rabbit in the hat here.


If you are looking for a balanced distribution of dynamic range on both sides of the of the approximate middle gray shooting with Dragon you will want to shoot between ISO 640-1600. You will notice a 1.3 stop variance in there, I'll go further into this in the next paragraph, as it's not really important. Notice I'm not calling this Native ISO, but rather lets call it the Balanced ISO or heck the more apt Base ISO.

Now, the actual truth. Since all of the dynamic range is accessible "all the time" at ISO values within the recommended operating range (ISO 250-2000) you are just exposing and rating for your midtone or 18% Gray.


http://www.artbyphil.com/temp/redDragonGraphics/phfx_redDragon_ISOFLUTEmulation.png

In the graphic I made if you make a note of each "quadrant", meaning the individual boxes outlined by white across the grayscale gradient (consider those each stops) you can see clearly how stops get placed above middle gray while also visualizing the compression and expansion of tones. When the tones are expanded in the shadows, and in particular if you are dipping into the noise floor at higher ISO values like ISO 3200, this can reveal image noise in the shadows and darks. In that graphic this is illustrated by being able to see banding in the darkest side of the gradient.

Adrian Jebef
02-12-2014, 05:14 PM
Though I think using a light meter has its merits in digital cinematography I find it impossible to feel confident using one for exposure unless one knows the Native Sensor ISO of the camera he/she is exposing for. Mark, perhaps you can enlighten me on how one uses a light meter correctly when exposing for an ISO RANGE between 200-2000?

Adrian Jebef
02-12-2014, 05:30 PM
Heh. There is no real "Native ISO". The cake is a lie. There is such a thing as base sensor sensitivity however and that's not what we're looking for though it's extremely important.

What many of us refer to as Native ISO is the balancing point and even distribution of dynamic range above and below the midtone (most measure it off of 18% Gray), though not the way most would likely desire to shoot. Meaning the approximate middle ISO rating.

It's actually a horrible term and I should remove it from this graphic and change it to Base ISO.

If you are looking for a balanced distribution of dynamic range on both sides of the of the approximate middle gray shooting with Dragon you will want to shoot between ISO 640-1600. You will notice a 1.3 stop variance in there, I'll go further into this in the next paragraph, as it's not really important. Notice I'm not calling this Native ISO, but rather lets call it the Balanced ISO or heck the more apt Base ISO.




For simplicity's sake a Sensor's Base Sensitivity, Native ISO, Base ISO, Balanced ISO, or simply ISO (as one would find on a can of 35mm film) is the same thing. In terms of "scene exposure" ISO is a camera's or film's mid exposure point where there is an EVEN distribution of usable stops above and below middle grey. This standard definition has been used for about 100 years. I'm still perpetually confused why RED prefers to define their cameras with an ISO Range (200-2000 w/ Dragon) instead of a nominal exposure mid-point.


Phil, in your opinion, what have you found to be DRAGON's mid-point ISO (ie: 8 over / 8 under)?

Jacobo Martinez
02-12-2014, 05:55 PM
Though I think using a light meter has its merits in digital cinematography I find it impossible to feel confident using one for exposure unless one knows the Native Sensor ISO of the camera he/she is exposing for. Mark, perhaps you can enlighten me on how one uses a light meter correctly when exposing for an ISO RANGE between 200-2000?

Taking into account what was said in this thread, you use the meter to create a look. This means if you dial in your meter iso 2000 you will get a look that has more highlight stops then shadows. The DR is more distributed in the highs. It is a look that you are maybe looking for a given story. But under the hood what you are doing is under exposing to have more highlights, or maybe because you are going for a textured look. then you compensate in the metadata chain with iso. Am I right mark?

Mark L. Pederson
02-12-2014, 05:59 PM
Mark, perhaps you can enlighten me on how one uses a light meter correctly when exposing for an ISO RANGE between 200-2000?


Sure Adrian - this is exactly what I did the first day I got a Dragon -

First of all I would get to know my "film stock" - which for this example is the Dragon sensor.

Default ISO by manufacturer (RED) = ISO 800. I'm was pretty confident based on my experience with MX that RED's default ISO would be slightly higher than what IMO was optimal for "most" situations. I liked MX at ISO 500. But I keep an open mind - it is - after all - a new film stock.

I do some simple tests - I start with 800 - so I set my light meter to 800 - I place a subject holding a color chart against a neutral background - I take an incident reading next to the face of the subject - I open up one stop for skin tones (caucasian) - and I shoot a shot. Then, I bracket - + and 1 to 4 stops over and under. Then I look at the R3D files in RCX - push and pull them. And I mentally process what I see - based on my subjective impressions of what I like as a look and my personal tolerance for noise.

I shoot some more "stress tests" trying to break the camera. How far can I push this guy? How far can I pull this guy? I'm amazed how well low ISOs look and work. I test high ISOs. They work as expected - I'm more blown away by low ISOs and color and dynamic range.

I pay attention to the in-camera exposure meters as well - I notice that it really feels like I have to open up MUCH more to clip. After bringing in clips into RCX - I notice that I want MORE information that the histogram shows me. I REALLY want the Exposure Tool in RAW view.

My initial reaction was that rating the ISO at 800 on Dragon appeared to me to be much more accurate than rating the MX to 800 with respect the light meter. Further - I personally liked where 18% gray landed with respect to dynamic range and noise with a bit more light hitting the sensor than the base exposure (ISO800) based on that exposure method - so - if suspected that 640 was what I wanted.

I re-rated light meter to 640. Shot more bracketed tests and reviewed in RCX - while checking Exposure Tool in RAW view. I felt very warm and fuzzy. So ... I knew ... for me personally ... 640 was my personal "base" ISO for a "non specific" project.

iI tested low light and found ISO 1280 more my speed than ISO 2000 - as I have a much lower tolerance for noise now that I look at 4K monitors and see everything. I test bright exteriors - I'm blown away by 250 and 320 compared to MX.


So ... what do I set the light meter to shoot my movie? Example:

Low Budget Horror movie. The film has some day exteriors - but mostly dark interiors - and lots of night exteriors.

What's the creative? I like high contrast. So ... I'm gonna want to lean to a lower ISO and higher contrast ratio - brighter lights. I have low budget. SHIT - can't afford tons of bright lights - need to compromise on the night exteriors a bit - shit.

I'd rate at ISO 400 for day exteriors, 640 for interiors, 1280 for exteriors.

So my Dragon is three film stocks for this project - or - one film stock rated three different ways. Could I shoot the whole film at ISO 640 - sure - but, I need all the help I can get on night exteriors while trying to keep the contrast up - and I like the look of low ISO bight, daylight exteriors.

Bill Anderson
02-12-2014, 06:04 PM
Shoot a test, using a spot meter, in order to evaluate/sync it with your chosen iso, and establish the iso's clipping point and max black with detail, it is then easy to PLACE values up and down that scale with impunity - you will never fear clipping or losing valuable shadow detail ever again. The power of the reflected light meter lies in its ability to show us relationships between every subject value - and since we know it reads everything at mid gray (18%) we can then see where values fall on the scale, and alter their position to suit our needs - as long as we have tested and accurately established the scale, just like the chart Adrian posted.
Take the iso 800 sample on the chart, we can see that anything at/above 7.4 stops above mid gray is clipped, and it's easy to see which scene values fall in or out of that zone if one is using a spot (reflected light) meter.

Adrian Jebef
02-12-2014, 06:10 PM
Sure Adrian -

I'd rate at ISO 400 for day exteriors, 640 for interiors, 1280 for exteriors.




OK. Interesting. What kind of meter do you prefer to use? Incident or Spot?

I'm interested in those of you who continue to use light meters w/ digital cinematography as I've basically all but tossed mine years ago. Looking back I don't think I've every worked with a DP who selectively changed a film stock's ISO rating dependent on a particular scene (INT/EXT/DAY/NIGHT). Maybe if said DP was pushing or pulling the stock via processing but that will actually affect the film's exposure response, something that doesn't happen with cameras like DRAGON.

Mark L. Pederson
02-12-2014, 06:13 PM
OK. Interesting. What kind of meter do you prefer to use? Incident or Spot?

I'm interested in those of you who continue to use light meters w/ digital cinematography as I've basically all but tossed mine years ago. Looking back I don't think I've every worked with a DP who selectively changed a film stock's ISO rating dependent on a particular scene (INT/EXT/DAY/NIGHT). Maybe if said DP was pushing or pulling the stock via processing but that will actually affect the film's exposure response, something that doesn't happen with cameras like DRAGON.

I'm an incident guy - only because that's what I had in film school. That's what I "know". I could not afford a reflected meter.

I actually want to buy a new one - I think I'm gonna go Sekonic L-478D LiteMaster Pro - http://www.sekonic.com/products/l-478dr/overview.aspx

Jacobo Martinez
02-12-2014, 06:24 PM
I'm an incident guy - only because that's what I had in film school. That's what I "know". I could not afford a reflected meter.

I actually want to buy a new one - I think I'm gonna go Sekonic L-478D LiteMaster Pro - http://www.sekonic.com/products/l-478dr/overview.aspx

Phil Holland has a sekonic L-478, maybe he can tell us his experience using it.

Mark L. Pederson
02-12-2014, 06:25 PM
Looking back I don't think I've every worked with a DP who selectively changed a film stock's ISO rating dependent on a particular scene (INT/EXT/DAY/NIGHT). Maybe if said DP was pushing or pulling the stock via processing but that will actually affect the film's exposure response, something that doesn't happen with cameras like DRAGON.

I worked on tons of movies with two film stocks - one for interiors and night and one for daylight. That was pretty much the norm at the time.

Mark L. Pederson
02-12-2014, 06:26 PM
Phil Holland has a sekonic L-478, maybe he can tell us his experience using it.

Let's do that.

Yo Phil -

Should I buy that L-478?

Phil Holland
02-12-2014, 06:28 PM
For simplicity's sake a Sensor's Base Sensitivity, Native ISO, Base ISO, Balanced ISO, or simply ISO (as one would find on a can of 35mm film) is the same thing. In terms of "scene exposure" ISO is a camera's or film's mid exposure point where there is an EVEN distribution of usable stops above and below middle grey. This standard definition has been used for about 100 years. I'm still perpetually confused why RED prefers to define their cameras with an ISO Range (200-2000 w/ Dragon) instead of a nominal exposure mid-point.


Phil, in your opinion, what have you found to be DRAGON's mid-point ISO (ie: 8 over / 8 under)?


It's more than 8 over and under, which is why this is a bit tricky. It's just a bit more. Based on the latest calibration and OLPF I have measured a hair over 18 unique stops of clear separation between tonal full stops. However, that was flat REDlogFilm. Under a normal viewing gamma you are looking more into the 16.3-17 stop range of usable captured dynamic range, though that extra "goodness" is still there and accessible.

Given that it's the difference of dividing 16.3 and 18.alittlebitmore by two. So in that regard the Base ISO again falls between that 1.3 stop range I mentioned ealier. ISO 640-1600.

And if you're interested I feel this is why many will be shooting ISO 640, 800, 1000, 1250, and 1600 on Dragon. You can play devils advocated and just extract the center value from that and say ISO 1000 if you want (though not the best thing to do). That allows for aproximately 2/3rds of a stop variance on either side. So think about what that would mean in terms of absolute clip, readable highlight and absolute "Super Black", measurable tonal separation in shadows.


Long and the short of it, the Base ISO of Dragon falls within ISO 640-1600 as of the latest calibration. If you want a what I would describe as a hard sweet spot number I'd say it's about ISO 1125 (weird number) based on all that data.


Will shooting at only that ISO get you the best results in every situation? Not necessarily.

If you are curious a good chunk of those shooting abroad with Dragon on rating for ISO 800 and going with that.

Shooting at lower ISOs below 800 helps produce a cleaner look and distributes more dynamic range "weighting" in the shadows. Vice versa, shooting at a higher ISOs above 800 places more dynamic range in highlights and you will see more "texture" across shadows and midtones. Nothing new there.

To note something. The published cinema ready usable range of ISO 250-2000 is a 3 stop range. ISO 640/800 fall in the middle of that range. Just something to note.


Also, side note as a particular film stock was mentioned earlier in this discussion. Even Kubrick and Larry Smith pushed 5298 +2 stops on Eyes Wide Shut. I've had crazy, crazy conversations with filmmakers over the years about what "digital films" should look like. I've also done many "look" tests. Red cameras were once marketed as a "digital film alternative" and I do think this explains a bit of their popularity. Shooting, rating, and exposing for different ISOs should be considered like shooting different film stocks. Though obviously digital isn't exactly as noisey. If you enjoy a cleaner look favor lower ISOs. If you want subtle textured character higher ISOs might be worth exploring. It's up to you. With ISO you are merely rating your midtones and in effect subtly defining the overall look of your material.

Phil Holland
02-12-2014, 06:36 PM
I'm an incident guy - only because that's what I had in film school. That's what I "know". I could not afford a reflected meter.

I actually want to buy a new one - I think I'm gonna go Sekonic L-478D LiteMaster Pro - http://www.sekonic.com/products/l-478dr/overview.aspx


Phil Holland has a sekonic L-478, maybe he can tell us his experience using it.


Yo Phil -

Should I buy that L-478?


I like it overall. The weird bit is that the spot meter is something you have to "attach" and isn't always on. I am also mostly an incident meter guy, though I use the spot a good deal on more visual effects and technical related tasks. The spot meter is a 5 degree meter and I know some have criticized that, I've oddly enjoyed it's "broadness". Touch interface is sometimes a bit tricky when attempting to scroll values, but beyond that I like it a lot.

It's compact and has a nice big screen and that's very useful.

Mark L. Pederson
02-12-2014, 06:39 PM
I like it overall. The weird bit is that the spot meter is something you have to "attach" and isn't always on. I am also mostly an incident meter guy, though I use the spot a good deal on more visual effects and technical related tasks. The spot meter is a 5 degree meter and I know some have criticized that, I've oddly enjoyed it's "broadness". Touch interface is sometimes a bit tricky when attempting to scroll values, but beyond that I like it a lot.

It's compact and has a nice big screen and that's very useful.

Thx Phil. Hmmmm ... based on that review I will need to do a "hands on" comparison with the L-758Cine.

Adrian Jebef
02-12-2014, 06:48 PM
Shoot a test, using a spot meter, in order to evaluate/sync it with your chosen iso, and establish the iso's clipping point and max black with detail, it is then easy to PLACE values up and down that scale with impunity - you will never fear clipping or losing valuable shadow detail ever again. The power of the reflected light meter lies in its ability to show us relationships between every subject value - and since we know it reads everything at mid gray (18%) we can then see where values fall on the scale, and alter their position to suit our needs - as long as we have tested and accurately established the scale, just like the chart Adrian posted.
Take the iso 800 sample on the chart, we can see that anything at/above 7.4 stops above mid gray is clipped, and it's easy to see which scene values fall in or out of that zone if one is using a spot (reflected light) meter.




Amen, Bill. It is as easy as you've made it out to be. This is why I find it so confusing that there are shooters like Mark who selectively change ISO on their meters and cameras.

If you test your camera (as an example DRAGON) and find it's ISO to be 800 via your own exposure tests or perhaps by the ISO printed on the box, what do you gain by changing that ISO later? You've only got 16 Stops. You don't get any extra stops in your highlights or shadows when you change to ISO 200 or 2000 on your meter or on your camera. Middle-Grey is the same. It doesn't change. It's a constant. Just because you are shooting a Day Exterior and decide to change your ISO to 400 that still doesn't change your "scene referenced" 18% Grey card. If proper exposure via your meter and scene referenced 18% Grey at nominal ISO 800 is T5.6 for a particular shot just because you change ISO to 400 doesn't mean proper exposure is now magically T4. It's still T5.6. When you change ISO to 400 and expose at T4 you are in effect over-exposing your shot by 1 Stop. To any photographer or cinematographer I'd think this would be important.

Thoughts?

Adrian Jebef
02-12-2014, 06:51 PM
I worked on tons of movies with two film stocks - one for interiors and night and one for daylight. That was pretty much the norm at the time.


Yeah, but I bet those two stocks had two different ISOs. Maybe 250D and 500T? The DRAGON has just one ISO. It is one stock, not 2 or 3 or 100.

Mark L. Pederson
02-12-2014, 07:01 PM
The DRAGON has just one ISO.

By what definition? And what form of measurement? And what tolerance for noise?

I'm sorry, but as far as I'm concerned - it's a range. And I personally see creative and technical advantages for rating it differently for different situations and subject matter.

If you believe that one should only rate the camera ONE way - with ONE ISO - you can do that.

Jacobo Martinez
02-12-2014, 07:07 PM
Yeah, but I bet those two stocks had two different ISOs. Maybe 250D and 500T? The DRAGON has just one ISO. It is one stock, not 2 or 3 or 100.

Correct me if I am wrong, but from what understand, ISO in RED is a Look, a feel, a tool for the story.

Jacobo Martinez
02-12-2014, 07:17 PM
Sure Adrian - this is exactly what I did the first day I got a Dragon -



I do some simple tests - I start with 800 - so I set my light meter to 800 - I place a subject holding a color chart against a neutral background- I take an incident reading next to the face of the subject - I open up one stop for skin tones (caucasian) - and I shoot a shot. Then, I bracket - + and 1 to 4 stops over and under. Then I look at the R3D files in RCX - push and pull them. And I mentally process what I see - based on my subjective impressions of what I like as a look and my personal tolerance for noise.

Mark, I got confused from the comment you made about exposing with an incident meter. It is highlighted in green. When you use incident meter, the value the photometer meter would be the correct exposure for middle gray. You dont have to stop 1 stop for caucasion skin. If you use a spot meter and read the caucasian skin tone, than you would add one stop to the reading. Am i wrong?

Bill Anderson
02-12-2014, 07:18 PM
I use the one degree spot almost exclusively. Why, because it can show every value in a scene, and consequently you know the relationship of each value with another's, and their relationship with the EI scale; thus, it allows you to place those values exactly where you want them on that scale. You can place your highlight values just this side of clipping every time you desire, without a look at a monitor or scopes and what not. Same goes for shadow detail. You want to check your lighting ratio or use an incident meter? use your hand: place your hand where you would place your incident meter and, using your spot meter, take a reading and open up one stop. Done. Or use a gray card and don't open up one stop ( :

Just one more way to skin that cat I guess.

Mark L. Pederson
02-12-2014, 07:19 PM
This is why I find it so confusing that there are shooters like Mark who selectively change ISO on their meters and cameras.

Read post #54 again in this thread.

Adrian Jebef
02-12-2014, 07:24 PM
By what definition? And what form of measurement? And what tolerance for noise?

I'm sorry, but as far as I'm concerned - it's a range. And I personally see creative and technical advantages for rating it differently for different situations and subject matter.

If you believe that one should only rate the camera ONE way - with ONE ISO - you can do that.



I'm referring to history here, Mark. ASA / ISO / Native Sensor Sensitivity / 18% Grey are all constant values per their respective host (ie: film stock, digital camera, scene referenced middle-grey). They do not fluctuate. These values have always been defined as the middle-point or middle-value that best expressed an equal distribution of dynamic range both above and below said value. There's always a range of DR but the mid-point is forever fixed.

I would think it more difficult to work your exposure based off of different ISOs than by simply sticking to the Base ISO (as Phil likes to call it). If you know your camera's Base ISO then it's a breeze checking scene exposure values with a light meter. If you're above or below 8 Stops you're in trouble. If you're within tolerances then you're good. But if you all of a sudden change to 200 ISO now you've got 12 Stops below but only 4 Stops above. Shooting a Day Exterior this way could be easily detrimental. Plus you'll need to constantly refer back to an ISO/DR chart that shows the redistributed above/below mid-grey exposure stops when ISO is changed in camera. Seems a bit complicated way of working when the fundamentals of ISO and exposure are, in fact, super simple.

Adrian Jebef
02-12-2014, 07:29 PM
Correct me if I am wrong, but from what understand, ISO in RED is a Look, a feel, a tool for the story.


Only if you are using ISO as a "development" value. When exposing on set for a specific scene the ISO is a fixed value.

D Fuller
02-12-2014, 07:35 PM
OK. Interesting. What kind of meter do you prefer to use? Incident or Spot?

I'm interested in those of you who continue to use light meters w/ digital cinematography as I've basically all but tossed mine years ago. Looking back I don't think I've every worked with a DP who selectively changed a film stock's ISO rating dependent on a particular scene (INT/EXT/DAY/NIGHT). Maybe if said DP was pushing or pulling the stock via processing but that will actually affect the film's exposure response, something that doesn't happen with cameras like DRAGON.

But it does. You push or pull the development of the r3d just as we did with film. And it changes the image's response, just as it did with film.

D Fuller
02-12-2014, 07:38 PM
Only if you are using ISO as a "development" value. When exposing on set for a specific scene the ISO is a fixed value.

But how do you do one without doing the other? Raising the ISO on a Red camera is very much like push-processing film. You under-expose, knowing that you will develop the exposure in a particular way when you process the footage.

Jacobo Martinez
02-12-2014, 07:40 PM
But it does. You push or pull the development of the r3d just as we did with film. And it changes the image's response, just as it did with film.
+101

Jacobo Martinez
02-12-2014, 07:42 PM
But how do you do one without doing the other? Raising the ISO on a Red camera is very much like push-processing film. You under-expose, knowing that you will develop the exposure in a particular way when you process the footage.

Exactly the same! 100% agree, iso is a creative desicion that serves the story.

Adrian Jebef
02-12-2014, 07:45 PM
Read post #54 again in this thread.


Mark is Correct.

And the application of this is called shooting the "Toe" or shooting the "Shoulder",

Its a common practice for film guys through history until the Vision Stocks came out. Most DPs shot only 200TASA (5293) stock and never set there light meters to 200ASA ever.
They would shoot day and night because the early 500ASA was so grainey or as we say now noisey (sad that grain is called noise, so negative)and shooting different stocks was always jarring in the edit.

If you are going for a darker look, night interior, you shot test for the toe, the bottom of the stocks DR and sensitivity. You are going for blacks, skin exposure and protecting grain,not concerned with highlights, it not interior and you can put practicals on dimmers.

You might find that rating the film at 500 gave you much better results because you found some extra DR in this chemical batch of film which ranged quite a bit in the 90s. From 200ASA to 500ASA is a doubling of light. That is a huge amount a light at 200ASA you don't need now.

And vice versa with shooting "shoulder."

If you are going for skies or highlights or windows, you shoot and test for the Shoulder. And rate the same stock accordingly maybe at 100ASA to get that cloud detail.

Just because DR is there, doesn't mean that that info has to go on the screen, you get to choose, that's your call.



find your Toe or Shoulder sweet spot.

I decide to shoot the shoulder or toe and ETTR.
I never had a problem getting a black in post so I tend to open up for Night interiors and stop down for day exteriors

If 800 is clipping, always ND if you can to the native rating of the camera that's always the best, if youre out of ND and you need to roll the ASA down to hold the skies just do it. Your contrast will go up, so pull some out in your look settings,




Though this is true in respect to exposing a film negative, there is no "knee" or "shoulder" in digital cinematography. Film responds logarithmically, digital CMOS sensors like all of the RED cameras respond linearly. Though a gamma curve can be interpolated from a digital camera's linear code values the sensor has no log-esque response to scene referenced exposure the way film negative does. Though we may want to equate the two, the truth is they are basically complete opposites when it comes down to exposure response.

Zeb B
02-12-2014, 07:56 PM
I expose Red with very similar thinking, and that's where ISO has become important again -- not the camera's ISO setting, but ISO as a reference for light levels in front of the lens. I know that the sensor is about 320 ISO native, but I don't love the completely-clean image I get at 320 for most things. At 800, I get a bit of very pleasant noise, which I like, and the added benefit of some headroom that lets me roll the highlights off nicely. But for things like tabletop and package shots, I usually want a "fatter negative" with more color and a bit less noise, so I expose for 640 or 500, knowing I have to watch the highlights more carefully, but knowing that it will do things to the image that I want. Or as with Gunleik's image above, I can underexpose and get an image where darks cluster together and mix with noise a bit, and the hilights occupy most of the long slope of the tonal curve. All with a sensor that has a fixed response.




thank you

Mark L. Pederson
02-12-2014, 08:00 PM
Though this is true in respect to exposing a film negative, there is no "knee" or "shoulder" in digital cinematography. Film responds logarithmically, digital CMOS sensors like all of the RED cameras respond linearly.

Sure Adrian - but the logic and example still applies. If you want to exploit more of the dynamic range in the shadows or want to light for a higher or lower contrast ratio, etc. etc. etc.

I don't know about you - but creatively - it's a compromise to me to shoot all subject matter - in all situations - at the same fixed ISO just because there's and equal number of stops above and below 18% grey.

Adrian Jebef
02-12-2014, 08:05 PM
But it does. You push or pull the development of the r3d just as we did with film. And it changes the image's response, just as it did with film.


Actually it doesn't. With film negative you are in essence "pushing" and "pulling" the logarithmic response curve when you push or pull process at the film lab. The "knee" and "shoulder" of the film negative's response curve is elastic. It bends and stretches. This isn't true with digital cinema cameras like the DRAGON. Though you can change ISO later in RedCineX in the development phase, and the gamma curve will shift, and this will seem to be the same response that one would get with film, the underlying data values present in the original R3D are still linear code values. They are not elastic. The big difference between the two is that when you push or pull film negative you are actively affecting your scene referenced exposure. When doing "the same thing" with a DRAGON via RCX scene referenced exposure has already been set in stone. The top, bottom, and mid-point of your DR will not change.

With the advance of modern digital cinema cameras like the DRAGON this difference becomes much more academic than real-world. Though if one goes back in time and shoots with the RED ONE this difference becomes all the more apparent.

Adrian Jebef
02-12-2014, 08:10 PM
Exactly the same! 100% agree, iso is a creative desicion that serves the story.



No. ISO is a technical value defined as the middle point where dynamic range is evenly distributed above and below said value.

Your chosen exposure for the scene is the creative decision that serves the story.

Adrian Jebef
02-12-2014, 08:55 PM
I don't know about you - but creatively - it's a compromise to me to shoot all subject matter - in all situations - at the same fixed ISO just because there's and equal number of stops above and below 18% grey.



ISO is a static, reference value (or it should be... hint, hint RED). ISO doesn't dictate your exposure choices. You do.



Say you're shooting a high-key day exterior shot. Maybe something in the desert. 21mm lens. Sun clearly visible in your frame. Sand dunes in the distance. And your main character front and center. Maybe something like this but with the sun in the shot as well:


http://www.quixote.com/blog/wp-content/uploads/2013/08/Lawrence-of-Arabia-600x362.jpg


Your incident meter tells you that proper exposure for your leading actor's face is T8. OK. You take a meter reading of the sun. Unsurprisingly it's 10 stops over "key" or your nominal scene referenced exposure based on subject matter (your actor) and ISO (800 via DRAGON). The bummer is you've only got 8 Stops over Key. What to do? Well you can easily close the lens down 2 stops to a T16. Problem is that now your Key or actor or scene referenced middle-grey/18% Grey is now 2 Stops underexposed. To get your Key back to proper exposure (creatively defined by you, the DP, not technically defined by ISO) you'll need to bring out a couple of 18K HMI's and punch in some fill light into your actor's face. Problem solved. You expose at T16. Your shot looks amazing.

Same scene, different approach: It's the desert. It's hot. Really hot. You're sweating. Your actor is sweating. You've just climbed up this stupid sand dune to get your incredible shot. It's gonna look amazing. But you'd really like a bottle of water. You take a meter reading of your actor. T8. OK. But you don't want to shoot with such a deep stop. You prefer shallow depth of field. You want to shoot at a T2. So you call to your trusty AC, "Throw in a N12!" Ooops. He left the filters back on the camera truck. It's gonna be 30min to get them. "Forget about it", you decide. My DRAGON is a 200-2000 ISO shooting machine! You'll just compensate for the exposure change in camera. Who wants to shoot day exteriors at 800 or 2000 ISO anyway? So you set your DRAGON to 200 ISO. That's only 2 Stops. Now according to your meter you should expose at T4. But you wanted to expose at a T2! Well, DRAGON has awesome dynamic range and it really has super nice highlight fall-off. You think to yourself, "I bet even if I overexpose by 2 whole stops it'll still be OK. After all DRAGON's got like 16+ Stops of DR!" If you're only left with 6 Stops over Key instead of 8 you think you'll still be fine. Maybe the sun does blow out a bit but the surrounding clouds should hold. You'll be fine. Problem is you've already shifted your DR via changing your camera and meter ISO. You don't have 6 Stops over Key, you probably have less than 3 or 4.

When you get the footage back home and pump it into RCX, approach 1 is perfect. You haven't clipped any highlight detail. You've got some range in the sun and surrounding clouds. And your actor's face is perfectly exposed. You can shift the developmental ISO from 200-2000 and it still looks great. It's all about how you want the scene to play: bright and hot or a bit more silhouette-y. It's another creative decision.

Approach 2 doesn't turn out so well. You realize you totally forgot to pump in 2 more stops of light into your actor's face. But it's cool cause you can just change your development ISO in RCX. Go from 200 back to 800. Though this helps your actor's exposure you also notice that the sun is completely blown out. As are most of the surrounding clouds. Totally clipped. Completely white. Zero detail. You take development ISO back down to 200. It's a compromise. Your actor is a bit too dark. You can probably help that out a bit later with a proper grade in Resolve. But surprisingly, the sun and surrounding clouds are still blown out. Still clipped. You see a bit more detail there but nowhere near enough to call your shot properly exposed. Worst of all is when your actor turns back into the sun to walk off into the distance. When his face hits the sun it goes completely nuclear. No hope.


This is just one example where ISO ranges like 200-2000 can be more confusing than helpful when one is learning how to expose properly in digital cinema.

Bill Anderson
02-12-2014, 08:58 PM
A lot of seasoned guys set up using an incident meter and then get out the spot to check and make sure everything is in play.

And good post, Adrian

Adrian Jebef
02-12-2014, 09:01 PM
A lot of seasoned guys set up using an incident meter and then get out the spot to check and make sure everything is in play.



Yup, and they do this based on a reference: ISO and Middle-Grey. The two are the same.


Thanks, Bill.

Bill Anderson
02-12-2014, 09:05 PM
Yep, good old "Zone V". Adams knew what the heck he was talking about.

Jacobo Martinez
02-12-2014, 09:10 PM
You can shift the developmental ISO from 200-2000 (tel:200-2000) and it still looks great. It's all about how you want the scene to play: bright and hot or a bit more silhouette-y. It's another creative decision. .

That is exactly what i am trying to say, exposure has nothing to do with iso, to change exposure in red camera it can only be made with shutter and changing the amount of light passing through the lens to the sensor either stopping up or down or using filters. Iso is a creative choice.

D Fuller
02-12-2014, 09:12 PM
Actually it doesn't. With film negative you are in essence "pushing" and "pulling" the logarithmic response curve when you push or pull process at the film lab. The "knee" and "shoulder" of the film negative's response curve is elastic. It's bends and stretches. This isn't true with digital cinema cameras like the DRAGON. Though you can change ISO later in RedCineX in the development phase, and the gamma curve will shift, and this will seem to be the same response that one would get with film, the underlying data values present in the original R3D are still linear code values. They are not elastic. The big different between the two is that when you push or pull film negative you are actively affecting your scene referenced exposure. When doing "the same thing" with a DRAGON via RCX scene referenced exposure has already been set in stone. The top, bottom, and mid-point of your DR will not change.

With the advance of modern digital cinema cameras like the DRAGON this difference becomes much more academic than real-world. Though if one goes back in time and shoots with the RED ONE this difference becomes all the more apparent.

I spent a lot of time thinking exactly this. And while it is not wrong, it misses the point. It doesn't matter where the tone curve gets applied. It does get applied. And once you accept that development decisions are part of exposure decisions (as they were in film: when you decided to push a stop, or decided to let the negative go thin, knowing that it would be printed down to keep the shadows dark and moody) then the craft of exposure becomes almost exactly like film. And in fact, by the time you push-process film, the exposure has already been made (just as when developing an r3d) and the push-process is part of the decision you made at the time of exposure.

I actually disagree just a bit with Mark's description of Dragon as 3 different film stocks. I see it as one "film stock" that can be exposed and processed in three different ways. In that way, it is the way I used to thick about Tri-X. Over exposed and undeveloped, it produced a very different look than normally exposed. Under-exposed and push-processed, it produced still another look. But before you did any exposure, I had to know how I was planning to develop.

Adrian Jebef
02-12-2014, 09:29 PM
Yep, good old "Zone V". Adams knew what the heck he was talking about.



The MAIN MAN he was. Adams defined how to expose creatively for any aspiring photographer or cinematographer.

A lot of the confusion surrounding proper exposure techniques for digital cinema in relation to ISO is that most think ISO is a singular expression when, in fact, it has become two. ISO in relation to a film stock or digital cinema camera is a rated value that when exposed at via 18% Grey will yield an image with an equal distribution of dynamic range above and below 18% Grey or stated ISO value. This is how ISO has always been defined. This is how light meters work, both incident and reflective. This is how Adams' Zone System is calibrated.

But today, in the ever changing digital landscape, ISO has made it's way into Post. Here it is no longer an exposure tool. It is now a development tool. In RCX changing the ISO does not change the captured dynamic range at all. Scene referenced exposure DR is static. It is a fixed range. When you change ISO in RCX you are shifting your captured DR in relation to a targeted gamma curve. You are actually not recovering any highlight or shadow detail. You would need to go back in time to your scene and change your lighting or exposure to do that. You are simply shifting where in the gamma curve your extreme highs and lows fall. Depending on what choices are made at this development stage you may or may not push out some part of usable DR. Again, it depends on the targeted gamma/color space and how much of a deviation you make from the camera's Base ISO.

If you haven't already, I highly recommend taking the time to read Ansel Adam's "The Negative" and "The Print". These two companion books are in essence the BIBLE on creative exposure choices across any and all photographic medium, whether digital or analogue. One can acquaint "The Negative" with a digital camera's Base ISO and "The Print" with the development ISO.


http://blog.depositphotos.com/wp-content/uploads/2012/02/anseladams1.jpg



BTW: "The Camera" is also highly recommended.

Adrian Jebef
02-12-2014, 09:42 PM
That is exactly what i am trying to say, exposure has nothing to do with iso, to change exposure in red camera it can only be made with shutter and changing the amount of light passing through the lens to the sensor either stopping up or down or using filters. Iso is a creative choice.


No. ISO is a technical, fixed value. Exposure is a creative choice. If you change your development ISO in Post it would be an intentional creative choice. One that you hopefully thought of in advance when you were on-set setting your scene referenced exposure. ISO tells you how to expose for an equal distribution of dynamic range both above and below middle-grey. Where you actually set your exposure defines what you find important in the scene.

Exposure has everything to do with ISO. How can you make a confident creative choice if you don't know the middle and limits of your exposure range (DR)?


Again, I highly recommend Ansel Adams' books on this subject. I have yet to come across a more elegant explanation of the technical and creative process than that which is found within the pages of his books.

Adrian Jebef
02-12-2014, 10:01 PM
I spent a lot of time thinking exactly this. And while it is not wrong, it misses the point. It doesn't matter where the tone curve gets applied. It does get applied. And once you accept that development decisions are part of exposure decisions (as they were in film: when you decided to push a stop, or decided to let the negative go thin, knowing that it would be printed down to keep the shadows dark and moody) then the craft of exposure becomes almost exactly like film. And in fact, by the time you push-process film, the exposure has already been made (just as when developing an r3d) and the push-process is part of the decision you made at the time of exposure.

I actually disagree just a bit with Mark's description of Dragon as 3 different film stocks. I see it as one "film stock" that can be exposed and processed in three different ways. In that way, it is the way I used to thick about Tri-X. Over exposed and undeveloped, it produced a very different look than normally exposed. Under-exposed and push-processed, it produced still another look. But before you did any exposure, I had to know how I was planning to develop.



Personally, I think both of us "get it". We've probably both spent enough time with film and digital formats that we're now accustomed to exposing them. The bigger issue is those with less of a background or simply with less experience. Explaining the technical and creative concepts of proper or intentional exposure is very important. Saying that so and so digital camera is amazing and has so much DR and shoots RAW and has a usable ISO range of 200-2000 misses the point. Describing a camera this way makes it seem that there are no compromises when one shoots RAW at 200 or 2000 ISO, when in fact there are many, many compromises.

You said it yourself, "once you accept that development decisions are part of exposure decisions then the craft of exposure becomes almost exactly like film". Exactly! This is why Adams' books have such relevance in the digital age. The difference between you or me and the newbie who has just purchased his first RED camera is that we know this very important distinction. Someone less experienced may take these ISO specs (200-2000 for DRAGON) at face value. They may change camera ISO to suit their scene referenced exposure without realizing that they have now shifted their entire dynamic range to a point where highlights clip or shadows get noisy. And then later, in RCX, they shift development ISO again because they think as long as the numbers are within 200-2000 their shot should look great. Sometimes it works. And sometimes it's a complete mess.

A cinematographer's creative exposure choices can only be made when he/she knows for certain what his camera's Base ISO rating and range are and what additional creative compromises he/she will make in the development phase (which is intrinsically tied to the scene referenced expose / Base ISO).

David Battistella
02-13-2014, 12:04 AM
I actually disagree just a bit with Mark's description of Dragon as 3 different film stocks. I see it as one "film stock" that can be exposed and processed in three different ways. In that way, it is the way I used to thick about Tri-X. Over exposed and undeveloped, it produced a very different look than normally exposed. Under-exposed and push-processed, it produced still another look. But before you did any exposure, I had to know how I was planning to develop.

and this was my point earlier in the thread.

I never said you could not rate the dragon at various ISO's but I do feel it's the manufacturers responsibility to "put a sticker on the film can" as it were. The concepts being discussed here are all correct. Toe and shoulder, rating higher outdoors than indoors.

I think the real problem is that most "shooters" are actually doing the opposite. They crank down the ISO outdoors and crank it up for dark interiors, not realizing that they are increasing grain and limiting DR by doing so. (Where is the craft going!)

The zone system is still one of the most solid exposure practices to go by.

So, in my poor english, or language choices, I'm not disagreeing with what is being discussed here and everyone has valid points, I'm just suggesting that the "dragon sensor film stock" be given a baseline ISO rating by the manufacturer as a suggested starting point. When I get my dragon, I would probably do exactly the same tests as mark did with different ratings and I might end up with a floating range as well (probably two) but I think the manufacturer should have one.

Oh, and the 800 ISO rating on the EPIC, I think the Alexa came out at about the same time rated at ISO 800, red was toying with rating MX at 500 (which would have been more accurate) but landed on 800 probably not to loose competitive advantage. I've always found 800 just a tad grainy on MX, and tend to process ass lower ISO's

Ok, I turn it back to back to the mad squad now. :)

battistella

Will Keir
02-13-2014, 12:11 AM
Adrian,

I like this graph, much better and more intuntive than Phil's version. Sorry Phil, your graphs are great but that one I didn't visualize as well as this one. The bars being vertical does something special.


BTW: I like Phil's graph but I believe it's a bit misleading in the way it shows "expanded" or "compressed" highlight/shadow with respect to the -2 and +2 stops of exposure. Looking at it, the graph seems to suggest that by opening or closing your exposure +/-2 Stops or changing your ISO you keep the same Dynamic Range end points but squeeze in or squeeze out more or less highlight/shadow detail. This is not how digital CMOS-based sensors work. They have a linear sensitivity to light unlike a film stock whose sensitivity is logarithmic. Scene exposure values become discretely coded into a digital camera's DR (ie: 0-1023 in a 10-bit scale), they do not bend or curve like film does. Technically, there is no knee or shoulder with a digital cinema camera. The exposure curve (gamma) is interpreted directly from the captured linear code values. Though the curve can be interpreted numerous ways via post transforms it has no bearing on the top and bottom end of scene exposure.

I prefer this graph on the relationship of a sensor's native Dynamic Range and ISO changes:


http://www.arri.com/mobile/apg/images/overview/exposure_index.jpg

Will Keir
02-13-2014, 12:15 AM
haha, your going to hate me Mark but this guy is using ISO to adjust exposure. 2:57 haha, thanks for the video. still watching.


You are a wise man Will.

watch this video -


http://youtu.be/k8ThmLwRs3g

David Battistella
02-13-2014, 12:24 AM
I have a hunch David B and I might have chosen a different spot. And I think that is good... :)

Or we could discover it is the exact same spot and that is also good. :)

But it is pretty futile for me to be in this discussion without having run my own tests, as you Mark and Phil (phil with the absolute latest) have hands on time with the sensor.

One thing I can say is that protecting highlights (WHILE STILL IMPORTANT) looks like it is not going to have to be as carefully monitored as the sensor clip/rolloff (even on the pre new OLF stuff) is much more gentle and organic than it is on EPIC MX.

Battistella

Gunleik Groven
02-13-2014, 12:34 AM
Or we could discover it is the exact same spot and that is also good. :)

But it is pretty futile for me to be in this discussion without having run my own tests, as you Mark and Phil (phil with the absolute latest) have hands on time with the sensor.

One thing I can say is that protecting highlights (WHILE STILL IMPORTANT) looks like it is not going to have to be as carefully monitored as the sensor clip/rolloff (even on the pre new OLF stuff) is much more gentle and organic than it is on EPIC MX.

Battistella

Agree...

From what I have read of our previous discussions, I think we maybe expose similarly, but with different methodology.

Evin Grant
02-13-2014, 12:35 AM
When I was at Brooks Institute in the 90s and taking "The Zone system" from Chris Rainer and Bob Smith (Chris was one of Ansel's last assistants) one of the first things we did was test the EI (Exposure Index) of our film. The reason was that despite the number on the box almost all films have a slightly different sensitivity depending on the developer and temperature used. I bought 100 rolls of the same lot of medium format Tmax 100 and I spent two weeks nailing down the exact EI and DR (which turned out to be EI 125 once processed). I have an entire 50 page book of various exposure and dynamic range tests that I had to produce before we were allowed to go out and shoot any real subjects.

here is one of the images I made in that class...
http://evingrantphoto.com/wp-content/uploads/2012/09/Sand-Nude.jpg
The jpeg really doesn't do the print justice unfortunately.

This is not any different than the approach you should take finding the EI you feel most appropriately matches your vision for the project you have on hand, regardless of the camera. I have tested the MX and the Dragon and happily expose those cameras at EIs from 320-1280 on the MX and 400-4000 on the Dragon depending on the look and needs of the scene. The rated EI/ISO on the camera are dead on accurate to 18% grey when checked with both incident and spot meters (which need occasional calibration too BTW).

However you look at it you have considerably more DR and control over your exposure than any previous group of filmmakers up to this point.
Deal with it!

David Battistella
02-13-2014, 12:45 AM
Agree...

From what I have read of our previous discussions, I think we maybe expose similarly, but with different methodology.


And the key will always be having the tool that makes the image we(the collective we) want. Pretty, gritty, sharp, grainy, over, under, what the artist is going for. The digital tool is more flexible now than ever.

battistella

Will Keir
02-13-2014, 12:46 AM
I see your point. It's crazy to think your adding more light on this dune to get the proper exposure. Even crazier, after your long hike up the dune that pushes you back one step for every two taken, that you will have 18k HMI's readily available.

So setting your Base ISO fixes you to a specific grain pattern in the footage? So pick the grain you like best for your movie and roll at that ISO? Cutting a scene at 250 ISO with 3200 ISO material will look distinctively different and jarring in the final edit?

So the method both Phil and Mark are suggest could be a possible total nightmare in post? Never thought of it like that before.

Variable Film Stock has met a challenging obstacle. I'd like to shoot a test scene for grain, shooting a shot reverse shot at the very different ISOs. I won't have a chance for another week or two, if anyone beats me to the punch, that would be cool.



ISO is a static, reference value (or it should be... hint, hint RED). ISO doesn't dictate your exposure choices. You do.



Say you're shooting a high-key day exterior shot. Maybe something in the desert. 21mm lens. Sun clearly visible in your frame. Sand dunes in the distance. And your main character front and center. Maybe something like this but with the sun in the shot as well:


http://www.quixote.com/blog/wp-content/uploads/2013/08/Lawrence-of-Arabia-600x362.jpg


Your incident meter tells you that proper exposure for your leading actor's face is T8. OK. You take a meter reading of the sun. Unsurprisingly it's 10 stops over "key" or your nominal scene referenced exposure based on subject matter (your actor) and ISO (800 via DRAGON). The bummer is you've only got 8 Stops over Key. What to do? Well you can easily close the lens down 2 stops to a T16. Problem is that now your Key or actor or scene referenced middle-grey/18% Grey is now 2 Stops underexposed. To get your Key back to proper exposure (creatively defined by you, the DP, not technically defined by ISO) you'll need to bring out a couple of 18K HMI's and punch in some fill light into your actor's face. Problem solved. You expose at T16. Your shot looks amazing.

Same scene, different approach: It's the desert. It's hot. Really hot. You're sweating. Your actor is sweating. You've just climbed up this stupid sand dune to get your incredible shot. It's gonna look amazing. But you'd really like a bottle of water. You take a meter reading of your actor. T8. OK. But you don't want to shoot with such a deep stop. You prefer shallow depth of field. You want to shoot at a T2. So you call to your trusty AC, "Throw in a N12!" Ooops. He left the filters back on the camera truck. It's gonna be 30min to get them. "Forget about it", you decide. My DRAGON is a 200-2000 ISO shooting machine! You'll just compensate for the exposure change in camera. Who wants to shoot day exteriors at 800 or 2000 ISO anyway? So you set your DRAGON to 200 ISO. That's only 2 Stops. Now according to your meter you should expose at T4. But you wanted to expose at a T2! Well, DRAGON has awesome dynamic range and it really has super nice highlight fall-off. You think to yourself, "I bet even if I overexpose by 2 whole stops it'll still be OK. After all DRAGON's got like 16+ Stops of DR!" If you're only left with 6 Stops over Key instead of 8 you think you'll still be fine. Maybe the sun does blow out a bit but the surrounding clouds should hold. You'll be fine. Problem is you've already shifted your DR via changing your camera and meter ISO. You don't have 6 Stops over Key, you probably have less than 3 or 4.

When you get the footage back home and pump it into RCX, approach 1 is perfect. You haven't clipped any highlight detail. You've got some range in the sun and surrounding clouds. And your actor's face is perfectly exposed. You can shift the developmental ISO from 200-2000 and it still looks great. It's all about how you want the scene to play: bright and hot or a bit more silhouette-y. It's another creative decision.

Approach 2 doesn't turn out so well. You realize you totally forgot to pump in 2 more stops of light into your actor's face. But it's cool cause you can just change your development ISO in RCX. Go from 200 back to 800. Though this helps your actor's exposure you also notice that the sun is completely blown out. As are most of the surrounding clouds. Totally clipped. Completely white. Zero detail. You take development ISO back down to 200. It's a compromise. Your actor is a bit too dark. You can probably help that out a bit later with a proper grade in Resolve. But surprisingly, the sun and surrounding clouds are still blown out. Still clipped. You see a bit more detail there but nowhere near enough to call your shot properly exposed. Worst of all is when your actor turns back into the sun to walk off into the distance. When his face hits the sun it goes completely nuclear. No hope.


This is just one example where ISO ranges like 200-2000 can be more confusing than helpful when one is learning how to expose properly in digital cinema.

Gunleik Groven
02-13-2014, 01:00 AM
ISO is a static, reference value (or it should be... hint, hint RED). ISO doesn't dictate your exposure choices. You do.



Say you're shooting a high-key day exterior shot. Maybe something in the desert. 21mm lens. Sun clearly visible in your frame. Sand dunes in the distance. And your main character front and center. Maybe something like this but with the sun in the shot as well:


http://www.quixote.com/blog/wp-content/uploads/2013/08/Lawrence-of-Arabia-600x362.jpg


Your incident meter tells you that proper exposure for your leading actor's face is T8. OK. You take a meter reading of the sun. Unsurprisingly it's 10 stops over "key" or your nominal scene referenced exposure based on subject matter (your actor) and ISO (800 via DRAGON). The bummer is you've only got 8 Stops over Key. What to do? Well you can easily close the lens down 2 stops to a T16. Problem is that now your Key or actor or scene referenced middle-grey/18% Grey is now 2 Stops underexposed. To get your Key back to proper exposure (creatively defined by you, the DP, not technically defined by ISO) you'll need to bring out a couple of 18K HMI's and punch in some fill light into your actor's face. Problem solved. You expose at T16. Your shot looks amazing.

Same scene, different approach: It's the desert. It's hot. Really hot. You're sweating. Your actor is sweating. You've just climbed up this stupid sand dune to get your incredible shot. It's gonna look amazing. But you'd really like a bottle of water. You take a meter reading of your actor. T8. OK. But you don't want to shoot with such a deep stop. You prefer shallow depth of field. You want to shoot at a T2. So you call to your trusty AC, "Throw in a N12!" Ooops. He left the filters back on the camera truck. It's gonna be 30min to get them. "Forget about it", you decide. My DRAGON is a 200-2000 ISO shooting machine! You'll just compensate for the exposure change in camera. Who wants to shoot day exteriors at 800 or 2000 ISO anyway? So you set your DRAGON to 200 ISO. That's only 2 Stops. Now according to your meter you should expose at T4. But you wanted to expose at a T2! Well, DRAGON has awesome dynamic range and it really has super nice highlight fall-off. You think to yourself, "I bet even if I overexpose by 2 whole stops it'll still be OK. After all DRAGON's got like 16+ Stops of DR!" If you're only left with 6 Stops over Key instead of 8 you think you'll still be fine. Maybe the sun does blow out a bit but the surrounding clouds should hold. You'll be fine. Problem is you've already shifted your DR via changing your camera and meter ISO. You don't have 6 Stops over Key, you probably have less than 3 or 4.

When you get the footage back home and pump it into RCX, approach 1 is perfect. You haven't clipped any highlight detail. You've got some range in the sun and surrounding clouds. And your actor's face is perfectly exposed. You can shift the developmental ISO from 200-2000 and it still looks great. It's all about how you want the scene to play: bright and hot or a bit more silhouette-y. It's another creative decision.

Approach 2 doesn't turn out so well. You realize you totally forgot to pump in 2 more stops of light into your actor's face. But it's cool cause you can just change your development ISO in RCX. Go from 200 back to 800. Though this helps your actor's exposure you also notice that the sun is completely blown out. As are most of the surrounding clouds. Totally clipped. Completely white. Zero detail. You take development ISO back down to 200. It's a compromise. Your actor is a bit too dark. You can probably help that out a bit later with a proper grade in Resolve. But surprisingly, the sun and surrounding clouds are still blown out. Still clipped. You see a bit more detail there but nowhere near enough to call your shot properly exposed. Worst of all is when your actor turns back into the sun to walk off into the distance. When his face hits the sun it goes completely nuclear. No hope.


This is just one example where ISO ranges like 200-2000 can be more confusing than helpful when one is learning how to expose properly in digital cinema.



Actually Adrian, You will be able to get the sun "within" and the actors face at "right" levels with that ISO change in post. As RLF (like LogC) is constructed to "hold the top" even when pushed in post. As long as you do not actually overexpose, you get an emulated "roll-off" when you push the top.

So it seems like I disagree, but I do not... :)

Because your actors face will not look like you want it to, because of the underexposure.

So we agree... :)
NOT because you lose the top (as RED/ARRI and probably Sony/Canon have thought a lot about that and gone full circle back to Cineon or "cineon-like" logs to solve that), but because two stops underexposure does not LOOK the same when lifted up, as the "right" exposure does.

A couple of reflectors sounds easier to carry in that desert than that genny-truck truck and the 18k's, though... :)

I like this example. :)

David Battistella
02-13-2014, 01:01 AM
When I was at Brooks Institute in the 90s and taking "The Zone system" from Chris Rainer and Bob Smith (Chris was one of Ansel's last assistants) one of the first things we did was test the EI (Exposure Index) of our film. The reason was that despite the number on the box almost all films have a slightly different sensitivity depending on the developer and temperature used. I bought 100 rolls of the same lot of medium format Tmax 100 and I spent two weeks nailing down the exact EI and DR (which turned out to be EI 125 once processed). I have an entire 50 page book of various exposure and dynamic range tests that I had to produce before we were allowed to go out and shoot any real subjects.

This is not any different than the approach you should take finding the EI you feel most appropriately matches your vision for the project you have on hand, regardless of the camera. I have tested the MX and the Dragon and happily expose those cameras at EIs from 320-1280 on the MX and 400-4000 on the Dragon depending on the look and needs of the scene. The rated EI/ISO on the camera are dead on accurate to 18% grey when checked with both incident and spot meters (which need occasional calibration too BTW).

However you look at it you have considerably more DR and control over your exposure than any previous group of filmmakers up to this point.
Deal with it!


Hi Evan,

Great image. JPEGS NEVER do prints justice.

The interesting thing is that when you tested the TMAX100 you "discovered" a rating very close (almost exactly) to what the manufacturer suggested. With that knowledge you could move things around. You are fortunate to have had such great teachers who would force that kind of knowing into your image making. But the films rating and the one you discovered did not deviate much from a starting point or "set standard" under know circumstances. From that point you could rate that film wherever you wanted to for whatever creative choices you could make.

But the baseline exists to test against.

If that TMX was labeled 250-2000 it's your guess. You still would have needed to 100 rolls to figure out that it was about 125.

I'm just saying that very few people are going to go into that journey of discovery and many in RED's pool aren't going to take the time to do that kind of extensive testing, which is why my point in this thread is about establishing and having baselines.

Thank you! (even accidentally) because your post identifies the need for this perfectly.

Even after attacking TMAX on a technical level, your result was pretty darn close to what Kodak was telling you. From then on it's of to the creative races. While I would advocate ever single RED cutover and eyery single DP do this for every shoot, we know that not everyone is going to be the diligent student you were, blessed with those teachers.

Battistella

BTW: check out this trailer for a film I made about photographer George Tatge last year http://www.georgetatge.com (was nice to be in the darkroom again).
https://vimeo.com/52810195

Gunleik Groven
02-13-2014, 01:04 AM
Adrians above example illustrates another somewhat confusing point, that ISO may not necessarily be used equally in post and on set...

Evin Grant
02-13-2014, 01:07 AM
As part of the real world testing I've mentioned above I have been looking at what it means to "Hard clip" the Dragon's highlights, one thing for sure is it handles it with aplomb...
(This is the current "old" OLPF)

Both shot at ISO 500 (it's actually pretty difficult to hard clip at higher ISOs)

The window frames are in direct sun, subject is lit by a window with blinds about 10 feet away.
http://www.evingrant.com/pics/DragonHL/ADR.jpg

this should be pretty self explanatory, sun behind thin clouds, no fill whatsoever.
http://www.evingrant.com/pics/DragonHL/ODDR.jpg
The crunchy-ness is all Jpeg BTW.

You can download R3d frames & 1/4 Rez Tiffs here to play with...
http://www.evingrant.com/pics/DragonHL

This is obviously hard testing, but even without any DR bump the considerably more natural clipped highlight handling and organic grain structure make the Dragon upgrade a must for me.

Adrian Jebef
02-13-2014, 01:13 AM
Adrian,

I like this graph, much better and more intuntive than Phil's version. Sorry Phil, your graphs are great but that one I didn't visualize as well as this one. The bars being vertical does something special.




Glad it worked for you. I know it's almost considered sacrilegious around here but I pulled that graph off of ARRI's ALEXA FAQ page. If anyone is so inclined I'd recommend a visit or two over to "the dark side" as there is a ton of useful material to be found there (as is in their downloadable white papers).

http://www.arri.com/camera/digital_cameras/learn/alexa_faq/

The truth is both the EPIC and the ALEXA are basically the same camera by design. They're both just high-end video cameras. Just because they can shoot raw doesn't make them intrinsically better than a camera that can't. The ALEXA practically proves this point: if you run exposure and DR tests between recording compressed ProRes Log vs uncompressed raw the differences are amazingly subtle. Everything you can learn about digital cinema from ARRI's site applies directly to the EPIC or DRAGON. And everything you can learn from RedUser applies directly to the ALEXA. The only difference between the two is that I find ARRI to be a bit more transparent. But perhaps that is due to their history and experience as a company. Perhaps they are a bit more pragmatic when it comes to specs and definitions concerning their products.

David Battistella
02-13-2014, 01:14 AM
Adrians above example illustrates another somewhat confusing point, that ISO may not necessarily be used equally in post and on set...

True, but with film development you could never slide ISO the way you slide it around as metadata now. I ever find I have to swing ISO more than a stop to stop and a half at the very most. But it comes down to correct exposure at the start.

then you have all the other stuff there too. lift gamma gain, individual channel control, brightness, exposure, flut, photoshops style tools, resolve style tools, all in there to further "mess" things up.

that is another thread Gunleik! The one about simplifying post. You have me longing for the days of RED ALERT, which they should bring back fro about 90% of users.

Battistella

http://www.f8films.com/stills/redalert.jpg

Gunleik Groven
02-13-2014, 01:19 AM
Glad it worked for you. I know it's almost considered sacrilegious around here but I pulled that graph off of ARRI's ALEXA FAQ page. If anyone is so inclined I'd recommend a visit or two over to "the dark side" as there is a ton of useful material to be found there (as is in their downloadable white papers).

http://www.arri.com/camera/digital_cameras/learn/alexa_faq/

The truth is both the EPIC and the ALEXA are basically the same camera by design. They're both just high-end video cameras. Just because they can shoot raw doesn't make them intrinsically better than a camera that can't. The ALEXA practically proves this point: if you run exposure and DR tests between recording compressed ProRes Log vs uncompressed raw the differences are amazingly subtle. Everything you can learn about digital cinema from ARRI's site applies directly to the EPIC or DRAGON. And everything you can learn from RedUser applies directly to the ALEXA. The only difference between the two is that I find ARRI to be a bit more transparent. But perhaps that is due to their history and experience as a company. Perhaps they are a bit more pragmatic when it comes to specs and definitions concerning their products.

LOL, I knew where you got it. hahahahaha

I have seen it a couple of times.

You are right, the cameras work in many ways around the same principles. They are more similar than different. In fact, the more I know, the more similar do I find all digital cameras, RAW or not.
You just have to take "codec" into consideration, in addition to all the above... :)

And as mentioned, one of the things arri and red do share, is that they will keep whatever info is in the top available in post, no matter what iso adjustments you do to get things back to where you want them.

Problem with the at approach is as mentioned that skin 2 stops under does not look like skin at intended exposure. On the Dragon the cost - image-wise - is "smaller" than on MX. That is not to say it is not there.

A lot of things outside luma-levels change when you over/underexpose. The Character of the image basically changes, and while you can use ISO adjustments (in post) to correct for that AND keep the highlights, you do not necessarily get the image you intended.

David Battistella
02-13-2014, 01:20 AM
As part of the real world testing I've mentioned above I have been looking at what it means to "Hard clip" the Dragon's highlights, one thing for sure is it handles it with aplomb...
(This is the current "old" OLPF)

Both shot at ISO 500 (it's actually pretty difficult to hard clip at higher ISOs)

The window frames are in direct sun, subject is lit by a window with blinds about 10 feet away.


this should be pretty self explanatory, sun behind thin clouds, no fill whatsoever.

The crunchy-ness is all Jpeg BTW.

You can download R3d frames & 1/4 Rez Tiffs here to play with...
http://www.evingrant.com/pics/DragonHL

This is obviously hard testing, but even without any DR bump the considerably more natural clipped highlight handling and organic grain structure make the Dragon upgrade a must for me.

Thanks Evin. I could see the highlights holding so much better in Gunleik's hardcore R3D stress tests, such friendly rolloff which got better with the new olpf.

Battistella

Adrian Jebef
02-13-2014, 01:24 AM
Actually Adrian, You will be able to get the sun "within" and the actors face at "right" levels with that ISO change in post. As RLF (like LogC) is constructed to "hold the top" even when pushed in post. As long as you do not actually overexpose, you get an emulated "roll-off" when you push the top.

So it seems like I disagree, but I do not... :)

Because your actors face will not look like you want it to, because of the underexposure.

So we agree... :)
NOT because you lose the top (as RED/ARRI and probably Sony/Canon have thought a lot about that and gone full circle back to Cineon or "cineon-like" logs to solve that), but because two stops underexposure does not LOOK the same when lifted up, as the "right" exposure does.

A couple of reflectors sounds easier to carry in that desert than that genny-truck truck and the 18k's, though... :)

I like this example. :)





I always enjoy a good convo w/ you, GG.

In my above example I made it clear that the sun was metered 2 full stops above the intended creative exposure value. To expose the actor's face at the intended exposure of T8 you would have invariably overexposed the sun by 2 full stops. There was only 8 stops of DR over middle-grey (the actor's face) available. The sun was 10 stops over. That is why one needs to close down the lens by 2 stops and expose at a T16 to hold detail in the sun (I know this is a bit far-fetched as what does "hold detail in the sun" even mean! It's just an example, go with it). If you instead kept your exposure at T8 and then brought it down 2 stops later with development ISO in RCX the sun would still be overexposed by 2 stops. The development ISO gamma curve may stretch or pull the top end of your exposure values a bit and create a different sense of the top-end tonal curve but any actual detail would still be 100% lost and unrecoverable.

Adrian Jebef
02-13-2014, 01:28 AM
Adrians above example illustrates another somewhat confusing point, that ISO may not necessarily be used equally in post and on set...



Ta-Da !!! Mind Blown !!!


:emote_22_yikes:

Gunleik Groven
02-13-2014, 01:32 AM
Ta-Da !!! Mind Blown !!!


:emote_22_yikes:

I tried to explain... :)

It is not all hard, and I have seen it be used like that on both Alexas and REDs

You do not blow the top IN POST by lifting it two stops to get the levels right in the face.

Problem with this method (which I have seen DPs rely on) is that the face will not look the same, even though the levels will be the same.

So we agree.

Exposure is about light, even WHEN the top holds. due to post-ISO adjustments. :)

It is a nice security, but I really hate the unequal results people get when they "expose for the top" because you can do these adjustments, instead of exposing for "what is important".

It is BTW easy to test for this claim...

Gunleik Groven
02-13-2014, 01:37 AM
OK. Let's not go post, here... :)
Or let us make that a different thread. I introduced it, and just understood how that might not be good for the understanding of "ISO when exposing" :)

I think I might open another thread on the post side of these exact issues, though... :)

Signalchains... Each part of the chain is different and important to understand, but the one being discussed here, is the first... Photons hitting sensor. :)

Where it all starts and how to get it right.

I am so glad noone has not mentioned ETTR! :) hahahahahahahaha

Adrian Jebef
02-13-2014, 01:41 AM
I'd prefer ISO to be what it has always been: a discreet value based on a digital camera's dynamic range where ISO represents the mid-point or 18% Grey within that DR.

As for Post ISO, I'd get rid of it entirely. It's just confusing everyone more than it should. It would be better to simply redefine development ISO as a +/- numerical scale. IE: +1 Stop, -1 Stop. This is exactly how it used to work when we shot film negative by the way. You never shot a 500T film stock and then wrote "expose at 2000 ISO" on the can before you sent it to the lab. You simply wrote "Pull 1 Stop" or "Push Process 2 Stops".

Gunleik Groven
02-13-2014, 01:44 AM
I'd prefer ISO to be what it has always been: a discreet value based on a digital camera's dynamic range where ISO represents the mid-point or 18% Grey within that DR.

As for Post ISO, I'd get rid of it entirely. It's just confusing everyone more than it should. It would be better to simply redefine development ISO as a +/- numerical scale. IE: +1 Stop, -1 Stop. This is exactly how it used to work when we shot film negative by the way. You never shot a 500T film stock and then wrote "expose at 2000 ISO" on the can before you sent it to the lab. You simply wrote "Pull 1 Stop" or "Push Process 2 Stops".

I like that thought.
Now, there are a couple of controls in RCX that do exactly the same, but with different names... :)
Even the curves are ruled by the same main maths.

We are getting into terminology issues here, and in a way, I think that is not a bad idea.

But for the matter of clearity, I think this thread should stay in the "photons hitting sensors" domain... :)

NOW I have to get some work done...

Adrian Jebef
02-13-2014, 01:50 AM
NOW I have to get some work done...



And I need to get some sleep before the sun comes up. Till next time, cheers! :beer:

Hrvoje Simic
02-13-2014, 03:54 AM
I'd prefer ISO to be what it has always been: a discreet value based on a digital camera's dynamic range where ISO represents the mid-point or 18% Grey within that DR.

As for Post ISO, I'd get rid of it entirely. It's just confusing everyone more than it should. It would be better to simply redefine development ISO as a +/- numerical scale. IE: +1 Stop, -1 Stop. This is exactly how it used to work when we shot film negative by the way. You never shot a 500T film stock and then wrote "expose at 2000 ISO" on the can before you sent it to the lab. You simply wrote "Pull 1 Stop" or "Push Process 2 Stops".

Yes.

This would avoid a lot of confusion, underexposed imagery and "Red skintone" threads.

I'd also suggest putting that in the camera setting instead of making people believe they have a variable ISO medium. ISO is related to captured density depending on sensitivity. Which is not variable.

16 bits, RAW, higher DR and very clean shadows do not entail a variable sensitivity, they merely bring less penalties for missing a sweet spot. This is not an equivalent to variable ISO film stock, it is just more "flexible".

In this example changing ISO setting is not changing sensitivity of the medium or adding overall density but serves as a tool for re-destributing that density within the achievable DR.

Base ISO > evenly distributed around a mid point,
+ ISO > more density in the highlights, less in the shadows,
- ISO > vice versa

Mark L. Pederson
02-13-2014, 04:05 AM
I'd prefer ISO to be what it has always been: a discreet value based on a digital camera's dynamic range where ISO represents the mid-point or 18% Grey within that DR.

As for Post ISO, I'd get rid of it entirely. It's just confusing everyone more than it should. It would be better to simply redefine development ISO as a +/- numerical scale. IE: +1 Stop, -1 Stop. This is exactly how it used to work when we shot film negative by the way. You never shot a 500T film stock and then wrote "expose at 2000 ISO" on the can before you sent it to the lab. You simply wrote "Pull 1 Stop" or "Push Process 2 Stops".

Adrian you have some excellent posts while I was sleeping :)

And I now think I really understand what David has been driving at this whole time.



No. ISO is a technical, fixed value. Exposure is a creative choice. If you change your development ISO in Post it would be an intentional creative choice. One that you hopefully thought of in advance when you were on-set setting your scene referenced exposure. ISO tells you how to expose for an equal distribution of dynamic range both above and below middle-grey. Where you actually set your exposure defines what you find important in the scene.

Okay - you guys want ONE ISO "rating" for the camera - like the ISO on the film can. Then, based on user preference and testing - they rate it any way they want - and of course - it does change where 18% grey is relative to the total dynamic range - and sometimes that's a choice.

What I was trying to say - is that creatively - I would not want to use one ISO rating for my exposure method because I would not want to shoot all things with the dynamic range equally distributed over/under 18% middle-grey.

So ... my example posted earlier is better expressed as Dragon = one film stock. I rate it how I want it based on what I want driving my exposure method. So ... my three ISOs for one film example is not three "film stocks" - but one film stock "rated three different ways".

Now ... I'm pretty damn sure based on my tests (OLD OLPF) on Dragon that the ISO that has equal dynamic range above and below is over 800 but below 1280 - the BIG question I have if you and David - if we do it this way - what constitutes dynamic range at the bottom with respect to noise tolerance? Are we talking about "usable dynamic range" - and if so - what sets the definition of "usable"?

Let's just say that it's ISO900 (800 and some Flut :)) - but I still like to rate at ISO 640 as my personal base. That is the same as how many DPs would rate a film stick differently than the number on the box.

And yes, your point about ISO in post - yeah - we never called it that - we always said push/pull +1 or +2, etc. and IT WOULD be helpful IMO if the post processing controls were renamed - I doubt RED will make that change now - but regardless - you have pointed out something I need to emphasize when teaching.

Again - really glad to have you posting here Adrian and I hope you will help me try to motivate RED to implement solid CDL and 3D LUT support because I think it's important - but let's save that for another day :)

Mark L. Pederson
02-13-2014, 04:13 AM
I'd also suggest putting that in the camera setting instead of making people believe they have a variable ISO medium. ISO is related to captured density depending on sensitivity and they are not variable.

Except all the other cameras let you change ISO in the camera and it's how lot's of folks expect to work.



Base ISO > evenly distributed around a mid point,
+ ISO > more density in the highlights, less in the shadows,
- ISO > vice versa

Well ... this is a great, simple explanation that is easy to teach - and now it has me really liking the "Base ISO" definition :)

as long as someone can explain to me how we judge/define what is dynamic range at the bottom with respect to noise, etc. - that is what I'm still unsure of - please advise -

David Battistella
02-13-2014, 05:17 AM
Adrian you have some excellent posts while I was sleeping :)

And I now think I really understand what David has been driving at this whole time.



Okay - you guys want ONE ISO "rating" for the camera - like the ISO on the film can. Then, based on user preference and testing - they rate it any way they want - and of course - it does change where 18% grey is relative to the total dynamic range - and sometimes that's a choice.

What I was trying to say - is that creatively - I would not want to use one ISO rating for my exposure method because I would not want to shoot all things with the dynamic range equally distributed over/under 18% middle-grey.

So ... my example posted earlier is better expressed as Dragon = one film stock. I rate it how I want it based on what I want driving my exposure method. So ... my three ISOs for one film example is not three "film stocks" - but one film stock "rated three different ways".

Now ... I'm pretty damn sure based on my tests (OLD OLPF) on Dragon that the ISO that has equal dynamic range above and below is over 800 but below 1280 - the BIG question I have if you and David - if we do it this way - what constitutes dynamic range at the bottom with respect to noise tolerance? Are we talking about "usable dynamic range" - and if so - what sets the definition of "usable"?

And yes, your point about ISO in post - yeah - we never called it that - we always said push/pull +1 or +2, etc. and IT WOULD be helpful IMO if the post processing controls were renamed - I doubt RED will make that change now - but

Mark,

I'm glad maybe my position, thoughts, ideas, are becoming more clear.

Evin's post earlier was a darn good example of how a manufacturer, in this case KODAK with TMAX100 film stock, came very close to there rating. You hand it to Evin (a young photography student at the time) and he does a hundred rolls of testing sensitivity and comes up with a rating of 125 (pretty darned close). SO it should be for anyone testing Dragon after RED has defined the baseline. It does not prevent anyone from chaining their methods based on scene requirements, it just gives a baseline.

Now what does that mean. It means KODAK felt confident in saying that this film would be (with slight deviation) pretty much correctly exposed if you metered and lit according to 100ISO. Could people eek more out of it? maybe, but the baseline for their terms of sensitive of black and white film was set. THEN, people over, under, pushed pulled, etc.

So, where is that for Dragon. It'd want it at the middle of the extremes probably favoring highlight protection (because its digital) by maybe having one stop more in the highlights over the shadows. Where that falls with DRAGON could be be anywhere from 640 to 1000 ISO but I would favor a less grainy image (my taste) SO maybe I would settle at 640 like you have.

I can't say for sure at this moment because I have not done my own testing in a wide variety of circumstances, but based on what I am seeing in R3D files, I'm thinking it might be a true 800 ISO sensor now.

I'm not talking about where RED puts the ISO as a default, but where it really sits. Maybe also rather than go with ISO, EI would be better.


Battistella

Here is a good KODAK link (http://motion.kodak.com/motion/uploadedFiles/US_plugins_acrobat_en_motion_newsletters_filmEss_0 6_Characteristics_of_Film.pdf), not everything applies to digital but at least you can see the factors that go into rating a films EI

Ale Houston
02-13-2014, 05:27 AM
Sorry Adrian, but in the approach 1 you are talking about having two 18KW HMI and in the approach 2 you have a crew that forgets ND filters in the desert.. That's really not the cameras fault.. You can't ask the camera to solve every production problem and still look for creative possibilities.. it does what it does and it does it beautifully..

I get your point with 18% grey, but in our experience, in a country like Paraguay were we only have two seasons (the soccer one and summer), exposing to 800 or 2000 in exteriors is to condemn every chance of highlight detail.. or it means putting a buck load of filters in front of the lens, which we prefer not to do..


ISO is a static, reference value (or it should be... hint, hint RED). ISO doesn't dictate your exposure choices. You do.



Say you're shooting a high-key day exterior shot. Maybe something in the desert. 21mm lens. Sun clearly visible in your frame. Sand dunes in the distance. And your main character front and center. Maybe something like this but with the sun in the shot as well:


http://www.quixote.com/blog/wp-content/uploads/2013/08/Lawrence-of-Arabia-600x362.jpg


Your incident meter tells you that proper exposure for your leading actor's face is T8. OK. You take a meter reading of the sun. Unsurprisingly it's 10 stops over "key" or your nominal scene referenced exposure based on subject matter (your actor) and ISO (800 via DRAGON). The bummer is you've only got 8 Stops over Key. What to do? Well you can easily close the lens down 2 stops to a T16. Problem is that now your Key or actor or scene referenced middle-grey/18% Grey is now 2 Stops underexposed. To get your Key back to proper exposure (creatively defined by you, the DP, not technically defined by ISO) you'll need to bring out a couple of 18K HMI's and punch in some fill light into your actor's face. Problem solved. You expose at T16. Your shot looks amazing.

Same scene, different approach: It's the desert. It's hot. Really hot. You're sweating. Your actor is sweating. You've just climbed up this stupid sand dune to get your incredible shot. It's gonna look amazing. But you'd really like a bottle of water. You take a meter reading of your actor. T8. OK. But you don't want to shoot with such a deep stop. You prefer shallow depth of field. You want to shoot at a T2. So you call to your trusty AC, "Throw in a N12!" Ooops. He left the filters back on the camera truck. It's gonna be 30min to get them. "Forget about it", you decide. My DRAGON is a 200-2000 ISO shooting machine! You'll just compensate for the exposure change in camera. Who wants to shoot day exteriors at 800 or 2000 ISO anyway? So you set your DRAGON to 200 ISO. That's only 2 Stops. Now according to your meter you should expose at T4. But you wanted to expose at a T2! Well, DRAGON has awesome dynamic range and it really has super nice highlight fall-off. You think to yourself, "I bet even if I overexpose by 2 whole stops it'll still be OK. After all DRAGON's got like 16+ Stops of DR!" If you're only left with 6 Stops over Key instead of 8 you think you'll still be fine. Maybe the sun does blow out a bit but the surrounding clouds should hold. You'll be fine. Problem is you've already shifted your DR via changing your camera and meter ISO. You don't have 6 Stops over Key, you probably have less than 3 or 4.

When you get the footage back home and pump it into RCX, approach 1 is perfect. You haven't clipped any highlight detail. You've got some range in the sun and surrounding clouds. And your actor's face is perfectly exposed. You can shift the developmental ISO from 200-2000 and it still looks great. It's all about how you want the scene to play: bright and hot or a bit more silhouette-y. It's another creative decision.

Approach 2 doesn't turn out so well. You realize you totally forgot to pump in 2 more stops of light into your actor's face. But it's cool cause you can just change your development ISO in RCX. Go from 200 back to 800. Though this helps your actor's exposure you also notice that the sun is completely blown out. As are most of the surrounding clouds. Totally clipped. Completely white. Zero detail. You take development ISO back down to 200. It's a compromise. Your actor is a bit too dark. You can probably help that out a bit later with a proper grade in Resolve. But surprisingly, the sun and surrounding clouds are still blown out. Still clipped. You see a bit more detail there but nowhere near enough to call your shot properly exposed. Worst of all is when your actor turns back into the sun to walk off into the distance. When his face hits the sun it goes completely nuclear. No hope.


This is just one example where ISO ranges like 200-2000 can be more confusing than helpful when one is learning how to expose properly in digital cinema.

Mark L. Pederson
02-13-2014, 05:31 AM
I can't say for sure at this moment because I have not done my own testing in a wide variety of circumstances, but based on what I am seeing in R3D files, I'm thinking it might be a true 800 ISO sensor now.

I'm not talking about where RED puts the ISO as a default, but where it really sits. Maybe also rather than go with ISO, EI would be better.

Battistella


Okay - but again - with respect to "where it really sits" - if we all agree that = same DR above 18% grey and same DR below 18% grey - HOW do you define the DR of the lower stops? Because I tolerate a lot less noise than other folks - so - what would the technical process be for defining the lower stops of DR?

When you do your tests, how exactly will you decide how many stops are below 18% grey?

That is what I am struggling with - maybe I'm missing something simple - if so - please advise

David Battistella
02-13-2014, 05:47 AM
Like you, I'm going to favor less grain. When the blacks get too grainy, I won't want to go there, so for me it will come down to acceptable amounts of noise/widest DR. I'll probably end up near your numbers. The dragon stuff is very low noise, from what I have seen. This could be considered conservative and people will push back (as many who insist on 800 for EPIC, where many are in the 320-500 range). I've always been in the 320-500 as noise is the main factor for me.

battistella


Okay - but again - with respect to "where it really sits" - if we all agree that = same DR above 18% grey and same DR below 18% grey - HOW do you define the DR of the lower stops? Because I tolerate a lot less noise than other folks - so - what would the technical process be for defining the lower stops of DR?

When you do your tests, how exactly will you decide how many stops are below 18% grey?

That is what I am struggling with - maybe I'm missing something simple - if so - please advise

Scott Crawley
02-13-2014, 06:16 AM
We are getting into terminology issues here, and in a way, I think that is not a bad idea.

Funny, that is where I was at the start, even in the false color thread. What's in a name? Everything. It turns out words have meaning! A definite meaning... Sometimes two. ;-)

Sorry, that mini rant was about American culture, not your command of the language. :-)

Mark L. Pederson
02-13-2014, 06:29 AM
Like you, I'm going to favor less grain. When the blacks get too grainy, I won't want to go there, so for me it will come down to acceptable amounts of noise/widest DR. I'll probably end up near your numbers. The dragon stuff is very low noise, from what I have seen. This could be considered conservative and people will push back (as many who insist on 800 for EPIC, where many are in the 320-500 range). I've always been in the 320-500 as noise is the main factor for me.

battistella

And THIS is the elephant in the room. You are asking for a technical specification that requires a subjective interpretation.

And this is why I keep teaching that it's a RANGE not an exact value.

I'm not being a jerk here - I would love for everyone to agree and feel warm and fuzzy - and I'm sure this thread is very helpful for some folks - but let's peel back another layer of the onion -

#1: scaling the image down - from 5K or 6K to HD or 2K - reduces the perceived noise. I have MANY times looked at a HD image from a MX and saw no perceived noise - but then when viewing in 4K/UHD - I could see more noise than I found acceptable.

#2: some cameras apply NR in the camera. RED does not. You CAN, obviously apply it in post. 2000 ISO low light images from Dragon stand up great with just a small amount of NR applied in post.

I have tested and proven - that taking a 6K image and scaling down to 4K/UHD AND applying a small amount of NR in post processing - holds more detail than scaling ARRI RAW 2.8K up to 4K/UHD. So ... it's not like NR is "cheating" - it's a real tool.

So ... obviously you don't want a "base ISO" for finishing in HD vs. 4K, right? Or a "base ISO" that strictly excludes NR post processing, right?

BUT ... in all seriousness - you can extend your dynamic range of your lower stops with NR post processing and scaling - and again - unless someone can show me some technical standard for how much noise is too much - it all ends up in a subjective interpretation - and that can be 1 full stop easy.

Again - I'm not trying to be a jerk here - if someone can explain to me how they would technically define how many stops of DR are below 18% grey I'm all ears.

David Battistella
02-13-2014, 06:57 AM
And THIS is the elephant in the room. You are asking for a technical specification that requires a subjective interpretation.

YUP. I want RED to determine that. We can then be subjective to their interpretation with our creative choices.




And this is why I keep teaching that it's a RANGE not an exact value.

I would teach this too, because it is a creative tool. But there is a reference point set by the manufacture, Like a 500ASA sticker on a film can.



I'm not being a jerk here - I would love for everyone to agree and feel warm and fuzzy - and I'm sure this thread is very helpful for some folks - but let's peel back another layer of the onion -

#1: scaling the image down - from 5K or 6K to HD or 2K - reduces the perceived noise. I have MANY times looked at a HD image from a MX and saw no perceived noise - but then when viewing in 4K/UHD - I could see more noise than I found acceptable.

You are not being a jerk. This needs to be determined based on FUTURE deliver formats 4K and beyond, therefore I would say it more important to be conservative for eventual 8K blowups. Let's pretend HD is dead.



#2: some cameras apply NR in the camera. RED does not. You CAN, obviously apply it in post. 2000 ISO low light images from Dragon stand up great with just a small amount of NR applied in post.

Again here, RED just needs to deliver the RAW image and people should sharpen to taste. Always believed this is the 100% correct direction by RED, an honest image.



I have tested and proven - that taking a 6K image and scaling down to 4K/UHD AND applying a small amount of NR in post processing - holds more detail than scaling ARRI RAW 2.8K up to 4K/UHD. So ... it's not like NR is "cheating" - it's a real tool.

So ... obviously you don't want a "base ISO" for finishing in HD vs. 4K, right? Or a "base ISO" that strictly excludes NR post processing, right?

Has to be excluded. Would Kodak consider how one person sharpens in LA compared to how they sharpen in NY? or Hong King? No. RED delivers the picture based on the future, not now. I son't agree with picking an base exposure based on HD finishes, but i would agree with one based on 4K or 8K finishes.



BUT ... in all seriousness - you can extend your dynamic range of your lower stops with NR post processing and scaling - and again - unless someone can show me some technical standard for how much noise is too much - it all ends up in a subjective interpretation - and that can be 1 full stop easy.

Again - I'm not trying to be a jerk here - if someone can explain to me how they would technically define how many stops of DR are below 18% grey I'm all ears.

Post tools should not be RED's concern, unless they were building that functionality into their own exposure tools. I never would sharpen with RED's tools in RCX as they produce little black artifacts in prints, etc. (that really needs to get straighten out)

Why? Because we can't predict that is the way it will be. They have to focus on the IMAGE CONTAINER, what goes into the R3D, that's it. Like a film shot 50 years ago scanned today at 6K is going have the benefit of tools that were not available at the time. But the container (the film) reveals more than it did or could then, compared to now.

RED should pack all they can into that container so that in 50 years the R3D's we extract will blow our minds based on how we can decode it then.

It's all about down the road, HD is in the rear view mirror.


Battistella

Mark L. Pederson
02-13-2014, 07:12 AM
Post tools should not be RED's concern, unless they were building that functionality into their own exposure tools. I never would sharpen with RED's tools in RCX as they produce little black artifacts in prints, etc. (that really needs to get straighten out)

Battistella

Well ... I am pretty sure that Kodak and Fuji took post processing into their ISO determination for film stocks.

You say "I want RED to determine that" - can you tell me, technically and subjectively, how you want them to "determine that"?

So ... RED picks a number - Phil picks a different number - and I pick a different number - they are all close - but all different.

Sounds like a RANGE to me.

But okay - since it's the manufacturer declaring it - it's "right" then?

I'm NOT saying RED should not just pick a number in the RANGE. But if you are gonna use that as your BASE ISO - then please enlighten me, and RED, how they should determine that number so that guys like me won't say - that's not the right number - the REAL number is XYZ :) Because THAT is exactly what is going to happen.

IMO - threads like this - and teaching people that "Native ISO" is really a RANGE not an exact number - is better for everyone.

But Adrian's comments and arguments are awesome and valid.

That said - I think we can squeeze that RANGE down a bit - make it more narrow. Right now - I'm gonna say Dragon it's between 800 and 950 - and again, in MOST situations - my preference will be to rate it at 640 - but I will wait until I get a new OLPF and then I will re-test EVERYTHING and I will tell you what the smallest RANGE I feel comfortable defining as "NATIVE ISO" - specifically for 4K finishing.


Good thread, huh :)

I love Reduser. I'm glad to be back.

Mark L. Pederson
02-13-2014, 07:28 AM
After more reading - The ISO 12232:2006 standard


"The ISO standard ISO 12232:2006[55] gives digital still camera manufacturers a choice of five different techniques for determining the exposure index rating at each sensitivity setting provided by a particular camera model. Three of the techniques in ISO 12232:2006 are carried over from the 1998 version of the standard, while two new techniques allowing for measurement of JPEG output files are introduced from CIPA DC-004.[56] Depending on the technique selected, the exposure index rating can depend on the sensor sensitivity, the sensor noise, and the appearance of the resulting image. The standard specifies the measurement of light sensitivity of the entire digital camera system and not of individual components such as digital sensors, although Kodak has reported[57] using a variation to characterize the sensitivity of two of their sensors in 2001."

and

"Noise-based speed[edit]
Main article: Signal to noise ratio (imaging)


Digital noise at 3200 ISO vs. 100 ISO
The noise-based speed is defined as the exposure that will lead to a given signal-to-noise ratio on individual pixels. Two ratios are used, the 40:1 ("excellent image quality") and the 10:1 ("acceptable image quality") ratio. These ratios have been subjectively determined based on a resolution of 70 pixels per cm (180 DPI) when viewed at 25 cm (10 inch) distance. The signal-to-noise ratio is defined as the standard deviation of a weighted average of the luminance and color of individual pixels. The noise-based speed is mostly determined by the properties of the sensor and somewhat affected by the noise in the electronic gain and AD converter.[55]"

"Despite these detailed standard definitions, cameras typically do not clearly indicate whether the user "ISO" setting refers to the noise-based speed, saturation-based speed, or the specified output sensitivity, or even some made-up number for marketing purposes. Because the 1998 version of ISO 12232 did not permit measurement of camera output that had lossy compression, it was not possible to correctly apply any of those measurements to cameras that did not produce sRGB files in an uncompressed format such as TIFF. Following the publication of CIPA DC-004 in 2006, Japanese manufacturers of digital still cameras are required to specify whether a sensitivity rating is REI or SOS."

180 DPI, huh?

Cough ... Cough ....

David Battistella
02-13-2014, 07:31 AM
But okay - since it's the manufacturer declaring it - it's "right" then?

It's not right or wrong. It's the starting point. Take vision stock (amazing stock) Kodak came up with an EI for that film. We can argue all we want, but they determined that, that did not make them right, but it did make them the company that said, "we made this and we think this." now people can disagree, but it's not up to me to determine that for Kodak, or for RED. :)




I'm NOT saying RED should not just pick a number in the RANGE. But if you are gonna use that as your BASE ISO - then please enlighten me, and RED, how they should determine that number so that guys like me won't say - that's not the right number - the REAL number is XYZ :) Because THAT is exactly what is going to happen.

Of course it will. But do you hear a bunch of talk around the ALEXA base rating? Not really because when people took out their meters and starting lighting the way they did with film, they were ending up with consistent results. With RED it's been 800-320-500, but that talk was there because metered results vary. Now, going back to Evin's test, you can see dragon is responding based on the ISO you set your camera and Meter too. That is great news, so I think these are old issues based on how things have "needed" to be done now.





IMO - threads like this - and teaching people that "Native ISO" is really a RANGE not an exact number - is better for everyone.

But Adrian's comments and arguments are awesome and valid.

That said - I think we can squeeze that RANGE down a bit - make it more narrow. Right now - I'm gonna say Dragon it's between 800 and 950 - but I will wait until I get a new OLPF and then I will re-test EVERYTHING and I will tell you what the smallest RANGE I feel comfortable defining as "NATIVE ISO" - specifically for 4K finishing.

Good thread, huh :)

I love Reduser. I'm glad to be back.

I agree. It's a great thread. Constructive and getting back to the way it was at the start. If I had a dragon in my hands I would probably be giving you better arguments, but I don't even like to argue, I think anything that from RED that removes ambiguity is great. Then we are free to be ambiguous about all this stuff and that stimulates discussion and creates an exchange of ideas. That gets rid of fanboyism and creates community.

Battistella

Patrick Tresch
02-13-2014, 07:32 AM
http://www.arri.com/mobile/apg/images/overview/exposure_index.jpg

Thanks Adrian,

Best visual explanation I've seen so far. Cool would be to have a real stripe from the actual Dragon sensor to get the noise feeling. Like in the old days a densitometry stripe. Or add a red noise stripe in the blacks between -5 and -9. So people understand that the blacks at iso 3200 aren't as clean as at iso 160. At iso 800 with the "old olpf Dragon" I see more like +6 -8 stops.

Pat

David Battistella
02-13-2014, 07:48 AM
180 DPI, huh?

Cough ... Cough ....

This is good reading.

A full frame tiff from a 6K stream out of RCX is...wait for it....72 DPI. So, they rate based on 2.5 times the DPI of computer monitor resolution.


Battistella