Dynamic Range

[Stephen Webb]

In the interests of being the first to post in this forum, I thought I'd ask cinematographers out there who've actually tested the camera what they think the dynamic range actually is.

I've yet to see a full and controlled exposure and latitude test, but what I've been hearing recently hasn't sounded too good. In fact one guy whose been testing recently has insisted that there's only 6 stops, something I find hard to believe (that'd be worse than DigiBeta) - but then I'm not a cinematographer.

Has anyone done any thorough tests?

[Álex Montoya]

I've heard it's three and a half stops.

[R. Gonzales]

I've heard it's three and a half stops.

Your Kidding Right? :biggrin: Aren't you?

Method

[Graeme Nattress]

See my earlier posts on Dynamic Range..... I posted grabs of a stouffer test wedge chart that allowed you to see the distinction between ~34 wedges. Each wedge is 1/3 stop. There's more detail in my post, but I'll leave the simple math above to the reader....

Graeme

[Álex Montoya]

ur Kidding Right? Aren't you?

Three and a half or two 3/4, can't recall well.

[R. Gonzales]

Thanks Graeme,

I remembered that post, But I think I'll go back and do another read and fully commit to memmory this time.

Method

[R. Gonzales]

Three and a half or two 3/4, can't recall well.

Acording to the step Wedge it's about 11.3 stops

method

[Graeme Nattress]

Don't give the game away. That's top secret :-)

[R. Gonzales]

Soooo,

for All those who are interested, Information can be found here:

http://www.reduser.net/forum/showpost.php?p=89624&postcount=43

http://www.reduser.net/forum/showthread.php?t=4904&highlight=Graeme+Nattress+dynamic+range

As for giving up secrets... Just wanted everyone on the same page (s) :biggrin:

Method

[Álex Montoya]

Obviously I was joking. I mean, the footage speaks for itself.

[R. Gonzales]

Obviously I was joking. I mean, the footage speaks for itself.

I Just got worried That I might Have missed something some where. It's cirtainly great to have a sence of humor, which I obviously need to work on.

Thanks

Method

[Stephen Williams]

Hi,

I think the reason people are seeing less than the 11.3 stops is that many people overexpose by ETTR. There is nothing left for highlight sparkles.

I am sure using a spot meter at 320 asa one would be able to work +/- 5 stops from there.

Stephen

[Graeme Nattress]

ETTR would assume you're exposing to keep sparkles in range though. I think what you're saying people do is ETFTTR, or expose too far to the right?

What ETTR means to me is put the brightest significant data as far right as you can without clipping it. The creative expertise comes in the word "significant".

Graeme

[Stephen Williams]

Hi Graeme,

On a still frame it's easy to see where the highlights are, as somebody moves a highlight off their watch (for example) may be +3 stops higher than anything else for a few frames leading to clipping.

Stephen

[Graeme Nattress]

Absolutely - that's where the "art" comes in.

Graeme

[Stephen Williams]

Absolutely - that's where the "art" comes in.

Graeme

Hi Graeme,

So using a light meter and allowing for some headroom is not such a silly concept after all!

Stephen

[Graeme Nattress]

It's not a silly concept. But neither is ETTR - they all act as means to inform you of what is the "best" exposure. All tools, all good tools, but the only exposure tool that really matters is the brain.

Graeme

[David Mullen ASC]

Also, there is the philosophical question of whether you want exposure decisions to be based on a momentary amount of clipping, like when a car drives by and the sun glints off of the surface. General practices is to give all the shots in a sequence the same density on the negative (with film), or same scene level exposure, so that shot-by-shot adjustments in overall brightness are kept to a minimum, lest more extreme corrections cause variations in grain / noise levels. This is the one problem with thinking of exposure in still photography terms. A sequence in a movie traditionally has to have a continuous textural feeling shot-to-shot.

[Stephen Webb]

Graeme,

I'd already seen your DR test and very useful it was too.

The problem is that I've recently heard from someone who has tested one of the first 100 cameras and they've insisted that (in their tests) the camera consistently shows 6 stops. Personally I don't believe that 'cause, even though I'm not a DP, I can see that in comparison to other cameras in the 8+ stops league it clearly has more range.

Thing is, this guy is a pro, and a well respected one and (importantly) independent. What I was looking for was anyone such as Mr. Mullen here, or maybe Mr. Mathers, who have actually had opportunity to do professional, independent latitude tests that tell me something different. The nearest I've seen are Mr. Wilt's tests (with Mr. Mathers I believe) that were apparently not in ideal circumstances (and which from memory show about 8 stops).

It's difficult to argue with someone when they appear to have done the only controlled independent tests and I've nothing really to set against that.

[Graeme Nattress]

Measuring dynamic range is tricky. Measuring high dynamic range accurately is trickier still.

1) you need a target that has greater DR than you're measuring. A backlit Stouffer with care to avoid ambient or reflected light has a 13 stop range. We can confirm that with a spot meter.

2) you need to know how to process the image. RAW conversion is new to a lot of video people.

3) you must define what DR is. If you have a different definition, you'll get a different result.

If someone says it gets 6 stops, then they're doing something seriously wrong.

The good thing with science, is you don't have to be independent - you just have to document your experiment.

As you point out, if a less than idea test in less than ideal circumstances (ie light contamination of the target) can gather 8 stops, then 6 is bogus beyond belief.

Graeme

[Stephen Williams]

Graeme,

I'd already seen your DR test and very useful it was too.

The problem is that I've recently heard from someone who has tested one of the first 100 cameras and they've insisted that (in their tests) the camera consistently shows 6 stops. Personally I don't believe that 'cause, even though I'm not a DP, I can see that in comparison to other cameras in the 8+ stops league it clearly has more range.

Thing is, this guy is a pro, and a well respected one and (importantly) independent. What I was looking for was anyone such as Mr. Mullen here, or maybe Mr. Mathers, who have actually had opportunity to do professional, independent latitude tests that tell me something different. The nearest I've seen are Mr. Wilt's tests (with Mr. Mathers I believe) that were apparently not in ideal circumstances (and which from memory show about 8 stops).

It's difficult to argue with someone when they appear to have done the only controlled independent tests and I've nothing really to set against that.

Hi Stephen,

I am sure Geoff Boyle will do some wedge tests before he stops shooting with the Red. He did the same last year with the SI camera on MC.

Funny thing is David Stump's tests were not so different to Mr Wilt's tests. There was a problem with the processing on those images. It seems so odd that nobody has done a set of wedges, I know I would within a few minutes.

Stephen

[Álex Montoya]

I believe too that the problem lies in processing. We've seen so much badly processed footage here that we know how the RED can look like when that happens.

[Stephen Webb]

It seems so odd that nobody has done a set of wedges, I know I would within a few minutes.

You'd think, with 100 cameras out there, that someone would have done this by now, wouldn't you?

Graeme, I do think that 6 is bogus beyond belief - I'm just in no position to counter the claim!

[Graeme Nattress]

I think people are out shooting cool stuff not geeky charts! You just have to have confidence we've shot the geeky charts to make sure the camera performs correctly. We have, and it does.

Graeme

[Stephen Williams]

I think people are out shooting cool stuff not geeky charts! You just have to have confidence we've shot the geeky charts to make sure the camera performs correctly. We have, and it does.

Graeme

Hi Graeme,

Unless I push (any & every) camera (or film stocks) to its limits & beyond in preliminary geeky testing I won't be able to make full use of it.

Stephen

[jbeale]

I'm not affiliated with Red, and I'm planning to do some geeky chart shoots and publish the data, but it won't happen until shortly before Christmas. Of course also dependent on the usual subject-to-change schedule.

Quoting X stops of DR without explaining in detail how that was measured, doesn't have much meaning to me personally, there's just so many variables as many have pointed out.

If you don't want to get into the tech details, I'd say the best way to get a handle on it is to shoot the same scene with Red and some camera you're familiar with, and compare the results. True, you need to be pretty good at raw processing before that comparison will mean much, but I think that's sort of the whole point with Red.

[Bruce Allen]

See my earlier posts on Dynamic Range..... I posted grabs of a stouffer test wedge chart that allowed you to see the distinction between ~34 wedges. Each wedge is 1/3 stop. There's more detail in my post, but I'll leave the simple math above to the reader....

Graeme

I get ~27 wedges on my HV20 (using exact same Stouffer chart) but I don't consider it to have 9 stops of dynamic range when I shoot. I'd hazard that HV20 has 7 "real world" stops max, Red 9.5 "real world" max. Very good but not quite as good as film. Hopefully the upgrade you guys are doing will improve that? Semi-OT, anyone tried using a DigiCon filter on a Red yet?

Bruce Allen
www.boacienma.com

[dino g]

We just did two days of testing with Emmanuel Lubezki on a very intense commerical shoot for GE. also this week, we did a Daughtry video with Martin Weisz, a series of Tangueray spots for FX with Joe Arnao directing and Steve Wacks as the DOP and last month we did a series of promos for E! with Snoop Dogg as the talent and Anthony Manler as the director and Ketil Dietrichson as the DOP, these were some of the higher end jobs. We did not geek out with wedges and charts, we actually shot professionally light setups and then judged the footage in color, scratch, redcine, redalert and we are doing film out tests.

these are setups with millions of dollars worth of lights and hundreds of thousands of dollars of labor hours setting them up. two of the jobs this week btw were actually 435 jobs and RED was there as a test...

RED blew them all away, not sure how many stop range that translates into, but the camera performed well enough for the top level cinematographers to want to use it for very big features, commercials and music videos.

The one thing that resonates from all of them is RED is better than film by 3 stops in the shadows and worse than film for 3 stops in the highlights. so the range is basically the same, it is just skewed toward the dark, so a great camera for low light and night shots, much better than film in that case. Not bad for bright stuff, but you must protect for the highlights.

this camera is the real deal. we are having nothing but success demo'ing it for large advertising agencies, production companies, high end post houses, producers, directors and DOPs.

sorry if i am not as technical as you guys, but i sit there and watch these people ( million dollar a year directors/ DP's & huge clients) react to the images that are coming off of the camera and it makes me laugh at this whole thread, the economics of this camera are unmatched and this is a business after all.

the camera will be as good as you are composing images and lighting them. shooting on film costs 10x (if not more) what it costs to shoot RED and there may be a .005 difference in quality. Use the camera and you will spend less time talking/writing about what ifs and more time shooting.

we are available to come out and do demos.

dino

[IAN SUN]

Those are some very bold statements dino, I'll show them to my investors... "Gimme more money guys!"

[dino g]

What Jim (AND TEAM) did was BOLD, we are all just the recipients of his generosity! If a multinational corporation that was focused on ST profits made this camera it would have taken 10 years and have been priced ten times more expensive. dont let anyone tell you this camera is less than...it is more than in so many ways.

[Joel Kaye]

so the range is basically the same, it is just skewed toward the dark, so a great camera for low light and night shots, much better than film in that case. Not bad for bright stuff, but you must protect for the highlights.

The proof is in the adoption rate. But I do wonder if they were using the best low light film they could get their hands on when they decided RED was better in the shadows. If so, that's impressive.

[Bill Goehring]

The advantages of bayer digital capture over film in low-light situations doesn't surprise me in the least.

When I made the move from film to digital stills in my commercial work several years ago, an improvement in grain and sharpness in low-light situations was one of the first improvements I identified early on in the transition.

Viva La Difference!

[Policar]

This makes me kind of wary. Looking at the chart, you can see that almost all the latitude is in the shadows and the anecdotal evidence supports this: 3 stops more in the shadows, 3 stops less in the highlights. You could push three stops (ISO 1200?) and have the same exposure latitude in both directions, but then it would be so grainy.

Three stops less in the highlights means you need 8 times less light before blow outs. There are situations (mostly exteriors) where this would pose a real problem. I don't understand why digital has so much trouble holding on to highlight detail. The camera still looks amazing, but this really seems like a limitation. A lot of DP's complain about too much shadow detail in Vision 2 500T, and I suppose this means that the 3 extra stops beyond this aren't too useful under conventional circumstances.

Not a deal-breaker, but this doesn't seem like the best news I've ever heard.

[Joel Kaye]

The camera still looks amazing, but this really seems like a limitation.

Well I think it just means you need a lot of ND outside. The first tests of white cars on black asphalt outside with no silks or anything looked good. All the white detail on those cars was there... I'm not worried. Plus, we haven't seen what the new daughterboard will do.

[Policar]

Well I think it just means you need a lot of ND outside.

Not really. Certainly that's a way to approach it, but if you want to retain highlight detail equal to film, you'd need to underexpose 3 stops which means significant grain and artifacts.

Of course, if you shoot at the right time of day and backlight and whatnot this isn't really a huge problem at all. But it's not ideal, really, and I don't think anyone should pretend it is. Still, in wysiwyg, I think it's easier to avoid egregious exposure errors to this mitigates this limitation a bit.

[jbeale]

I don't understand why digital has so much trouble holding on to highlight detail. The camera still looks amazing, but this really seems like a limitation. A lot of DP's complain about too much shadow detail in Vision 2 500T, and I suppose this means that the 3 extra stops beyond this aren't too useful under conventional circumstances.

Film is (very) non-linear and so is the human eye. CCD and CMOS sensors are generally linear, although nonlinear processing is almost always done (gamma plus additional grading "curves") before you see it in a viewfinder or on screen. Due to the linear sensor, digital can seem to have no highlight range but that's in some sense an illusion. If you are running the camera, just where "shadow" and "highlights" fall within the sensor range is your choice. If you expose digital like you would for film, you are more likely to clip your highlights.

I hadn't heard about "too much shadow detail", but that seems like an easy problem to solve... :-)

[Álex Montoya]

Remember that there is almost half a stop of highlight detail that doesn't appear unless you process the footage with -0.5 exposure.

I believe that underexposing 2 stops may not be a bad idea. We've seen RED footage of 2000 ASA that didn't look bad at all. I guess you could expose like going for 1000 ASA. That would give you the 2 stops and it's not grainy at all. Of course that would only be needed when you got a high dynamic range scene.

BTW, what's a "daughterboard"?

And DINO, I am a huge Lubezki fan. If you could elaborate a bit on what you did with him and his reactions. There was a rumour as well that he was gonna use the RED for his next flic. You know anyhting about that?

[dino g]

i will not speak about rumors, but this was a test that we did for a future job arranged by a producer for him.

the commerical was for GE, i have absolutely no idea what the product was and i was there for three days, all i know is there were lots of clouds and a waterfall, so all of this talk about the highlights is interesting because they were pushed to the limit with this test and he seemed very pleased with the results.

he was impressed with the RED, whether or not that translates into him using it for a 9 figure shoot is yet to be determined.

i will say he was a joy to work with as were all the directors and DOPs i mentioned earlier.

[jbeale]

BTW, what's a "daughterboard"?


In electronics, people call a smaller auxiliary circuit board attached to the larger main board a "daughterboard". Compare to "motherboard".

http://en.wikipedia.org/wiki/Daughterboard

[PaulClements]

Hi Graeme,

Unless I push (any & every) camera (or film stocks) to its limits & beyond in preliminary geeky testing I won't be able to make full use of it.

Stephen

Stephen, I'd be happy to bring my camera along if you want to do some independent tests. I'm guessing after Christmas will be the earliest opportunity but I'd be more than happy to.

Paul

[david farland]

Now here the thing.
11 1/3 sounds and is great but i've no relative measure to judge it.
Of course I haven't even got my camera yet. I know Graeme did this test well, even where he needed to get photoshop involved to be able to see the entire chart on one take.
But my point is what is a relative comparison..what would be the DR of say a Nikon D200 or 300 using the same technique and rigor as what Graeme did?
I guess someone could counter what's the point of comparing it with a D200 as well and I'd have no answer except it's one more tool in modelling the camera. So how would/does the camera DR compare to another known 'still or moving' camera using the same Stouffer technigue?

Dave,

ps: sounds a shame they don't make a Stouffer test strip with the black section like they do for the Chroma du monde where the black is simply a hole opening onto a black felt lined box to reduce reflections.

[Graeme Nattress]

The Stouffer doesn't need the black-hole because it's a transmissive chart. The tranmission of the black card it's mounted on (I'm handy with a craft knife) is essentially zero. We block out all stray light, so the whole chart is effectively sitting in a black hole.

As for a DSLR - I'd expect somewhere between 10 to 12, but it's hard to get linear pixel data out of their RAW software, so that makes it hard to plot the linearity graphs that I do. You could do the same kind of pixel peeing analysis though, but again, as you can see on the DPReview DR test charts, it's very hard to get the RAW software to show all the range the sensor is capable of.

Graeme

[Bruce Allen]

But my point is what is a relative comparison..what would be the DR of say a Nikon D200 or 300 using the same technique and rigor as what Graeme did?

Same wedge - Nikon D200.
http://www.dpreview.com/reviews/NikonD200/page22.asp
Canon EOS 40D
http://www.dpreview.com/reviews/canoneos40d/page20.asp

BTW, I'd hazard their estimates seem more conservative than Graeme's.



I guess someone could counter what's the point of comparing it with a D200 as well and I'd have no answer except it's one more tool in modelling the camera.



So how would/does the camera DR compare to another known 'still or moving' camera using the same Stouffer technigue?

As said above, my HV20 gets around 9 stops using the similar criteria to Graeme's.

Also, you've seen the extensive stuff on Cinematography.net, right?
http://www.cinematography.net/compare.htm

Note their Red tests were with done with an pre-production sensor, sub-optimal Red Cine settings, etc. Those need to be updated.

Bruce Allen
www.boacinema.com

[Graeme Nattress]

I don't see the CML style test of DR philosophically sound. Geoff does them that way because he's always done them that way, but to me, there's too many variable, too many images to compare, too much that can go wrong. I much prefer the DP review method, which for DSLRs would work better if RAW converters allows you access to the linear sensor data.

If you look at the DPreview links, to "ACR Best" settings for raw, the Canon goes from 5 to 37 (or 32 wedges) and the Nikon from 6 to 40, (or 34 wedges) which is bang in line with the numbers I quoted above :-), 32 being 10.6 stops, and 34 being 11.3 stops. I don't think better RAW software would make the numbers better, but would make measuring them and plotting them a lot easier :-)

Graeme

[david farland]

Thanks Graeme. I'll read more on your or others techniques for how to run the Stouffer test but right now I'm guessing the light source is behind the strip it it radiates or tranmits as you say and the box stops stray light. It's a beautiful 25 degree sat morning so I'm trying to supress the inner geek in reading up in Stouffer testing...but until I can see what the Red can do in showing the latitude in shadows and roll off it's highlights I must be content with figures. Talking about figures I always thought it was totally unfair that the eyes could only view 6.5 stops in a single moment but will vary it's iris/chemical response? as it scans a scene to get 20 stops. I'm guessing there's a bucket load of different things that come into play when viewing a moving image as opposed to a still image. Things like action/characters on screen, racking focus etc. Someone was telling me how left and right eyed people will scan a scene differently.

Dave

stoppress: Thanks Bruce!!!

[Emmanuel Cambier]

Hi Graeme

How does the red compare to the D200 in terms of signal to noise ratio?

Emmanuel

[Graeme Nattress]

Well, DR = SNR. I've not measured a D200, so I don't know precisely.

All the sensors out there, that are used for cinematography are totally linear, which means that when they clip, they hard clip. Therefore all their dynamic range is below that, ie shadow detail if you look at it that way. What you do when you expose is you set the base ISO so as to bias the exposure to give you some stops above a middle point and some stops below. Then you use a tonal curve to map that exposure range down to a view able range that looks nice and contrasty.

Graeme

[Emmanuel Cambier]

So the lower the ISO, the more headroom below and less above, and vice versa ?

Any chance of being able to create a LUT with those tonal curves in RedCine and then to upload it in the camera for monitoring ?

Emmanuel

[Michael Lindsay]

Hi Graeme

I'd be interested in hearing more about the previously mentioned tool that interpolated clipped channel info from any unclipped channels.. Having some low color accurate luma detail in blown highlights (even if it amount to not much better than clever noise) would be great..

Michael

[Thor Wixom]

This makes me kind of wary. Looking at the chart, you can see that almost all the latitude is in the shadows and the anecdotal evidence supports this: 3 stops more in the shadows, 3 stops less in the highlights. You could push three stops (ISO 1200?) and have the same exposure latitude in both directions, but then it would be so grainy.

Three stops less in the highlights means you need 8 times less light before blow outs. There are situations (mostly exteriors) where this would pose a real problem. I don't understand why digital has so much trouble holding on to highlight detail. The camera still looks amazing, but this really seems like a limitation. A lot of DP's complain about too much shadow detail in Vision 2 500T, and I suppose this means that the 3 extra stops beyond this aren't too useful under conventional circumstances.

Not a deal-breaker, but this doesn't seem like the best news I've ever heard.

Policar,

I had some time with a RED at Rivetal Rentals' open house about a week and a half ago. 1200 ISO looked really good! Yes it was grainier than 320 to 500 ISO, but no granier than Vision 2 500 T would have been under the same studio lights. The amount of grain was barely perceptible, and completely acceptable.

-Thor

[Graeme Nattress]

Michael, that control is in RedCine (Highlight) and RedAlert (DRX) and works very well. Nothing much to add other than "try it".

Emmanuel, the in-camera controls give you good LUT control, or in the future you'll be able to do it in our apps and upload to camera.

Graeme

[Floris Liesker]

The one thing that resonates from all of them is RED is better than film by 3 stops in the shadows and worse than film for 3 stops in the highlights. so the range is basically the same, it is just skewed toward the dark, so a great camera for low light and night shots, much better than film in that case. Not bad for bright stuff, but you must protect for the highlights.

So if you had lit the camera 3 stops under it would have had exactly the same DR and Sensitivity as the film you compared it to.
You wouldnt have said 'the camera is great for night shots and 'not bad' for bright stuff'. When you would treat it as if it was 640 ASA or higher stock this same camera would suddenly perform better in the highlights and worse in the shadows.

In general I think the image of the Red would be much more film-like if it was treated like 640 ASA or even higher. In post you would need to make a nice knee rolloff for the highlights, make sure nothing hits the 100% when exporting from Redcine or Red Alert.

I think in this RAW processing a lot of people make a lot of mistakes. They probably slide the exposure slider to the left [EDIT: I meant to the right] without realizing ths clips a lot of highlights that were there in the original footage. I've witnessed this happening more than once, and wrong conclusions were drawn from the clipped image.

[Graeme Nattress]

Sliding exposure to the left lowers the exposure, and would reduce clipping, not increase it.

There's a histogram and zebras so you can quickly and easily see clipping.

As for RAW processing, that's an art people will have to learn.....

Graeme

[Floris Liesker]

Sliding exposure to the left lowers the exposure, and would reduce clipping, not increase it.


Sorry, I meant to the right.

[Graeme Nattress]

That's why there's a "brightness" control to brighten up the image without clipping highlights so much, just crushing them.

Graeme

[Floris Liesker]

Ah good. Haven't touched that slider yet.

[Blue]

Policar,

I had some time with a RED at Rivetal Rentals' open house about a week and a half ago. 1200 ISO looked really good! Yes it was grainier than 320 to 500 ISO, but no granier than Vision 2 500 T would have been under the same studio lights. The amount of grain was barely perceptible, and completely acceptable.

-Thor

Hey Thor. What were you viewing the RED footage on to accurately compare its graininess to that of V2 500 T?

[Thor Wixom]

Hey Thor. What were you viewing the RED footage on to accurately compare its graininess to that of V2 500 T?

The crew at Rivetal were capturing 4k files and loading them into Smoke. They were zooming in, color correcting, etc.

It wasn't a side by side comparison between Red and Vision 2 500T. Just an impression from having worked with that film stock and knowing what it looks like in various lighting conditions. There were several there who agreed with me that 1200 ISO looked very similar.

Before my HDV days, that was my film of choice.

I plan to do some actual testing after I get my camera. That should be in about 30 days or less.

I have a client that wants me to show comparisons between Red and several of the popular film stocks, including Vision 2 500T.

I plan to post the results. I think they will be close to my impressions, but we shall see.

-Thor

[dino g]

to clarify, my comments come directly from one of the directors that shot with my camera as a test against 35mm, not sure what stock he used, i guess i can find out, but he also is very good friends with the owner of scratch and has used the program for many years and was able to manipulate the footage in a very advanced way in redcine... i am certain he knows what he is talking about, but i guess when you get your cameras and have 15 dinos (lights, not me) working on your job, you will be able to draw your own conclusions.

[I Bloom]

In the interests of being the first to post in this forum, I thought I'd ask cinematographers out there who've actually tested the camera what they think the dynamic range actually is.

I've yet to see a full and controlled exposure and latitude test, but what I've been hearing recently hasn't sounded too good. In fact one guy whose been testing recently has insisted that there's only 6 stops, something I find hard to believe (that'd be worse than DigiBeta) - but then I'm not a cinematographer.

Has anyone done any thorough tests?

I recently had a conversation with a director friend regarding DR on Red vs film based on my limited experience with the camera. My conclusion was that because RED's response curve is more linear than film, it all depends on where you put the noise. If you expose so that the noise is present in the image you will have tremendous range in your highlights. If you expose so that there is no noise, you will feel your highlights like on HD. That's not based on any science that's just my feeling having tried to shoot and light a little bit for a Red. Filmic, when exposed low, beautiful video when exposed higher. Almost seems like common sense.

I understand its important to try to quantify this, especially for your light meter. But I think there is a limitation to the usefulness of this quantification as well.

Rest assurred it's much more DR than conventional HD. Somewhere around film. If you expose to have similar amount of grain as film, you will have filmic highlights. That's my first impression.

IBloom

[Floris Liesker]

I If you expose to have similar amount of grain as film, you will have filmic highlights. That's my first impression.
IBloom

That's my impression as well. I do think however that filmgrain looks much better than the noise coming off the Red sensor. It doesnt seem to be completely random, I can detect vertical stripes in it. Hopefully that is where the new daughterboard will shine...

[Fergus Meiklejohn]

If you expose to have similar amount of grain as film, you will have filmic highlights.
IBloom

What exactly do you guys mean by "exposing to have a similar amount of grain as film"?

[jbeale]

I do think however that filmgrain looks much better than the noise coming off the Red sensor. It doesnt seem to be completely random, I can detect vertical stripes in it.

If you have the time to deal with it, it should be relatively straightforward to remove any fixed-pattern background noise. You shoot for a while with the lens cap on, average those frames together, and subtract that from your regular shots.

This kind of "dark frame subtraction" is standard practice for astronomy work. It works best in linear light, before you apply any gamma curves or any other corrections. Ideally it would be built into Redcine, or the camera itself. This technique will not help if there is something nonlinear going on or the pattern is not truly "fixed" (eg. temperature dependent).

[I Bloom]

What exactly do you guys mean by "exposing to have a similar amount of grain as film"?

Red by comparison to other mediums is low noise. But there is noise deep in shadows on all formats.

If you underexpose on Red, you will still have a pretty image with a lot of information. Just more noise.

On film, the response curve has a pronounced toe and shoulder, over or underexposing (especially on older film stocks) also affect the contrast as values are mapped onto different parts of the curve.

Since the response curve on Red is very linear, choosing an exposure means sliding values up or down a relatively uniform graph. Contrast isn't greatly affected by where you place those values. Instead you have harsh digital clipping at the top of the graph and greater noise response at the bottom. Personally I prefer noise, but the ultraclean look is growing on me, especially if you take it back to film.

Ian

[Policar]

I don't know the first thing about CMOS sensors, but considering that there's no electronic gain going on and all this ISO stuff is based around post-processing...

Wouldn't it be possible to electronically gain down the sensor to ISO 80, while still rating it at ISO 320, thereby shifting the two stops from the shadows to the highlights?

[jbeale]

Wouldn't it be possible to electronically gain down the sensor to ISO 80, while still rating it at ISO 320, thereby shifting the two stops from the shadows to the highlights?

All CCD and CMOS sensors have some absolute maximum exposure limit, the so-called "full-well" condition. In normal operation (simplified) a photon hits the sensor and generates a charge (electron) which is stored in a well (capacitor). After enough light has come in, the well is full. Any additional light during that exposure causes no more stored charge, so it is not measured. After the exposure, the charge is measured and the well is emptied, and then you start another exposure.

Now IF the red camera approaches "full well" exposure with the current system design (and I would expect it to, because that's what you do to maximize dynamic range) then you cannot electronically "gain down" the sensor. Well you could, but it would clip at the same exposure, it would just record as grey instead of white, so it would be of little use.

Geeky aside: if there was some electronic way to change the quantum efficiency of the sensor (electrons out per photons in) then you could indeed "gain down" the sensor, just like adding an external ND filter. That would be cool. Unfortunately I don't know of such a design. Maybe it does exist, I just don't know of it.

[Peter McCully]

Geeky aside: if there was some electronic way to change the quantum efficiency of the sensor (electrons out per photons in) then you could indeed "gain down" the sensor, just like adding an external ND filter. That would be cool. Unfortunately I don't know of such a design. Maybe it does exist, I just don't know of it.

Mmmmm.... The quantum chip. Next big breakthrough in imaging technology. Will Red be first I wonder?

[morpheusfilm]

The reason a DP is telling 6 stops is that he is measuring the range as a contrastt ratio- in other words he reads the best exposure for a scene and looks at how much contrast range holds detail. This is very subjective but common way for a DP to evaluate the real effective range. Basic daylight exposure requires at least a 5:1 contrast ratio capability in the recording media to represent it moderately well. The reason the other test is giving 11.3 stops is that it is more scientific in approach and it's basically under and over exposing an 18% grey card. You overexpose the card until it merges with white and then underexpose until it merges with black and then you have your range. By the way the 11.3 was really dissappointing to me as a DP as I'm able to get 10.7 stops with the Varicam or the new F900R with certain filter combinations. I figure those same tricks may juice the RED to 12 stops but ultimately it still pales in comparison to film which is in the 16-17+ range. This to me is the most significant shortfall of digital cinema formats, and I really believe that this is the main area that needs to be improved in the system to really claim the prize.

[morpheusfilm]

The reason a DP is telling 6 stops is that he is measuring the range as a contrastt ratio- in other words he reads the best exposure for a scene and looks at how much contrast range holds detail. This is very subjective but common way for a DP to evaluate the real effective range. Basic daylight exposure requires at least a 5:1 contrast ratio capability in the recording media to represent it moderately well. The reason the other test is giving 11.3 stops is that it is more scientific in approach and it's basically under and over exposing an 18% grey card. You overexpose the card until it merges with white and then underexpose until it merges with black and then you have your range. By the way the 11.3 was really dissappointing to me as a DP as I'm able to get 10.7 stops with the Varicam or the new F900R with certain filter combinations. I figure those same tricks may juice the RED to 12 stops but ultimately it still pales in comparison to film which is in the 16-17+ range. This to me is the most significant shortfall of digital cinema formats, and I really believe that this is the main area that needs to be improved in the system to really claim the prize.

[David Mullen ASC]

Well, remember that film has also been improving over the decades in terms of dynamic range -- something like 3-strip Technicolor was pretty contrasty and early Eastmancolor negative wasn't much better. I expect digital sensors to also keep improving in dynamic range over time.

[Floris Liesker]

it should be relatively straightforward to remove any fixed-pattern background noise. You shoot for a while with the lens cap on, average those frames together, and subtract that from your regular shots.

I've been trying to do exactly that, to get a 'fingerprint' of the sensor to substract that of the image. Unfortunately the pattern turned out to be very non-fixed. I could not make any logic out of it, except that it contained randomly appearing and disappearing vertical stripes. Maybe Greame found some logic in it and whispered it into his daughterboard's ear.

[I Bloom]

I've been trying to do exactly that, to get a 'fingerprint' of the sensor to substract that of the image. Unfortunately the pattern turned out to be very non-fixed. I could not make any logic out of it, except that it contained randomly appearing and disappearing vertical stripes. Maybe Greame found some logic in it and whispered it into his daughterboard's ear.

It seems possible that the camera already does some fingerprint subtraction.

IBloom

[Álex Montoya]

I don't know, Morpheus. When I look at the footage of Jannard at the races or at this pic (http://www.hdforindies.com/uploaded_images/D001_C003_071013_00113_flat.jpg), I find that it holds enough info. And the RAW conversion helps squeezing the latitude better than with the Varicam or the 900.

Regarding the fingerprint, I recall Jannard saying that they were gonna get rid of the fixed pattern noise, so I guess they are already using an algorithm, though it obviously doesn't work too well.

[david farland]

Apologies for some really dumb questions here.....

1. If film, I'm assuming this is negative stock, has this 16-17stop range...will the print also have this range and will i be able to see the 16-17 stops on the theatre screen?

2. Again, I have 16-17 stop material, what digital or filmic online processes can handle this degree of range?

3. Are there any electronic screens i.e. crt, lcd, digitial projectors etc that I can view this range on?

Dave

[Fredrik Harreschou]

Apologies for some really dumb questions here.....

1. If film, I'm assuming this is negative stock, has this 16-17stop range...will the print also have this range and will i be able to see the 16-17 stops on the theatre screen?

2. Again, I have 16-17 stop material, what digital or filmic online processes can handle this degree of range?

3. Are there any electronic screens i.e. crt, lcd, digitial projectors etc that I can view this range on?

Dave

2. Floating point compositing can handle any dynamic range AFAIK.

3. The Sunnybrook HDR display supposedly has a DR of 40,000:1. I'm not sure how to translate that to stops. There are probably others too. Not cheap.

[Graeme Nattress]

The only film neg curves I've seen are completely flat at the ends of a 4.0OD dynamic range of exposure. That's 13.3 stops. About 2.5OD (8.3 stops) of that range is linear (ie shadow detail and highlight detail are not in serious compression) I have no idea which usable motion picture film stock would achieve 17 stops (5.1OD range)!

[David Mullen ASC]

1. If film, I'm assuming this is negative stock, has this 16-17stop range...will the print also have this range and will i be able to see the 16-17 stops on the theatre screen?


As Graeme said, color negative is more like 13 and a half (maybe 14-stops, which is what Kodak usually says).

No, print stock has a smaller range. This is because: (1) copying film to film causes an increase in contrast (contrast is additive), so the negative has to be lower in contrast than the final print, and (2) when projecting an image onto a white surface, the black density (D-Max) in the print has to be very high in order to look black on the screen, so print stock is designed with a high contrast.

Now the advantages of color negative's wider dynamic range are: (1) more information in color-correction to play around with to optimize for the smaller dynamic range of film prints or video presentation, (2) more natural roll-off into white due to the flatter response to light at the high end of exposure, (3) greater ability to handle mistakes in overexposure.

[Harry Lime]

Well, remember that film has also been improving over the decades in terms of dynamic range -- something like 3-strip Technicolor was pretty contrasty and early Eastmancolor negative wasn't much better. I expect digital sensors to also keep improving in dynamic range over time.

And they were slow. I think the 3-strip process they use on "The Red Shoes" / "Black Narcissus" was 25asa and had a rather narrow DR. Perhaps similar to Kodachrome 25?

Both films looked stunning though.... (Jack Cardiff I humbly bow before you...)

[David Mullen ASC]

I've spent some time trying to figure out the ASA value of 3-strip Technicolor based on footcandles and f-stops being used on movie sets back then, plus the speeds of b&w film used inside the camera. Remember that the prism block split the light in half, and then the light had to pass through a deep narrow-cut filter. So I would suspect that the system lost at least three-stops before it even hit the film.

Kodak doubled the speed of its b&w stocks in 1938, which is when 3-strip Technicolor also doubled its speed, just in time for "Gone with the Wind". Then there were changes to the prism block and filters that improved speed, and in the mid 1940's, changed the color balance from daylight (scenes had to be lit by carbon arcs) to tungsten.

My estimate is that early 3-strip Technicolor was an effective 5 ASA. By 1938, for "Gone with the Wind", it had become around 10 ASA.

By the late 1940's, it was around 16 ASA. When Kodak introduced color negative in 1950, it was 16 ASA, which they said was "equivalent to currently available color processes." So that's another clue that 3-strip was around that speed by that time.

Another clue was that DP's regularly talked about needing 1000 fc on 3-strip sets, and most photography was done wide-open at f/2.8 on 3-strip -- so that's around 10 ASA.

Of course, you had some leeway to use less light and underexpose the negatives. When I saw a restoration of the 3-strip "Joan of Arc" I noticed that all of Ingird Bergman's close-ups were somewhat milky. I asked Bob Gitt, the restorer, about that and he said all of her close-ups were underexposed. Now maybe that was a stylistic choice or maybe she simply didn't want to act under the necessary footcandles to get a proper exposure.

[Harry Lime]

On the Criterion DVD of 'The Red Shoes' there is an interview with Jack Cardiff and if I remember correctly he talks a little about the lighting challenges due to 3-strip being so slow. I believe he also mentions some ASA values.

Can you imagine anyone working with such slow speed films these days?
(or a camera the size of a small fridge)

I'm not a DP, but a still photographer and am still trying to figure out how Brassi shot Paris at night with film around 20 asa and a f3.5 lens.

[Blue]

The crew at Rivetal were capturing 4k files and loading them into Smoke. They were zooming in, color correcting, etc.

It wasn't a side by side comparison between Red and Vision 2 500T. Just an impression from having worked with that film stock and knowing what it looks like in various lighting conditions. There were several there who agreed with me that 1200 ISO looked very similar.

Before my HDV days, that was my film of choice.

I plan to do some actual testing after I get my camera. That should be in about 30 days or less.

I have a client that wants me to show comparisons between Red and several of the popular film stocks, including Vision 2 500T.

I plan to post the results. I think they will be close to my impressions, but we shall see.

-Thor

Cheers mate. Look forward to the results.

[Bill Anderson]

Mr Lime, it's tough to say just how much artificial light was available for each of Brasai's night shots. And we're only seeing the successes. Many would be shot at dusk, and not necessarily the dead of night. Nonetheless, the conditions would be pretty challenging. You not only have to consider the film, but the developers that were being used for such conditions. It's amazing just how much you can pull out of a neg with 45 minutes and more developing times with staining developers, Amidol, and waterbath treatments and the likes. Often followed by "intensification" chemistry. These guys were wizards at pulling out the latent image.

[Bill Anderson]

Harry, something I should also add, and I'm not sure if this was common practice in Brassai's era, pre-exposing (presensitizing) film to boost its sensitivity under low light conditions is quite effective. The fog produced in the lower values was just printed through. And this method also helped keep in check the added contrast of reciprocity failure. I think this method has even been used in motion picture techniques. Perhaps for different reasons though. Mr Mullen.. ?

[David Mullen ASC]

The term "latensification" has been used in motion picture lab work, but it usually just means low levels of flashing or chemical fogging -- true latensification involves very low and long exposure so that the reciprocity effect kicks in, allowing some build-up of photons but not an increase in base fogging. The idea is that it gives barely-exposed silver halide crystals just enough photons to make the crystals "developable".

Flashing can seem to increase shadow detail by lifting the blacks, but there is very little true increase in detail. I remember some tests of the Panaflasher vs. the Varicon by Mark Woods, and one odd thing noticed was that the increase in shadow detail was a little better with the Varicon, which flashes the image through the lens by producing a veil of light over the front of the lens, a controlled glare so to speak. For some reason, the fact that the image was simultaneously flashed, as opposed to pre or post-flashed as with the Panaflasher, boosted the shadow detail.

In really old tube video cameras, there was something called a bias light which had a similar effect in boosting low-level detail, although its main purpose was to reduce image lag.

I ran across an old article in a 1950's issue of "American Cinematographer" which said that Columbia Studios was requiring all movies in the B-Unit to use Plus-X b&w negative using a latensification process to allow them to reduce light levels. I guess this was somehow cheaper for Columbia (which did its own b&w processing back then) than using a faster Kodak b&w stock (like Super-XX or later, Tri-X). But I don't think it was true latensification.

[Gregor Hagey]

Has anyone done any thorough tests?

I just posted this on exposing for RAW, but perhaps my comments are more relevant here.

My conclusion from the Stouffer chart tests are that processing the .r3d in Red Alert at 320 ISO with -.40 exposure gives you the most latitude. You can apply a slight inverted 'S' curve to pull more out of the shadows and highlights, but the resulting image is very low contrast which is great for exporting for colour grading, but not a good look for editorial. When applying a slight inverted ‘S’ curve by eye I can read 24 steps, but by a waveform monitor 27 steps are definitely visible which equals 9 stops of dynamic range.

Upon analysing the steps on a waveform I noticed that they don’t change on a logarithmic scale. The steps should be in 1/3 stop increments, but at the knee the first two steps are expanded and cover an entire stop each and at the toe the steps are compressed and cover only 1/10 stop. Just like other video cameras there is plenty of information in the shadows, but it’s important to protect your highlights. On a waveform 10 steps (3 1/3 stops) can be seen above 50% and a whopping 17 steps (5 2/3 stops) below 50%. For the purpose of capturing the most dynamic range placing middle grey at 30-35 (instead of 50-55) on your zebras is the best way to go. When I set the camera to 320 ISO (archaically called ASA in the menu) and expose for 30-35% zebras on the viewfinder and then check the T Stop against my incident meter I actually end up with 320 ISO. It seems Red has already built this concept into the ISO settings on the camera. If I want to expose middle grey for 50-55% zebras I need to overexpose by 2 stops. This results in a cleaner image, but you risk clipping the highlights and reducing your overall dynamic range.

So far my real world experience matches these conclusions. You will get into trouble if you underexpose from the ISO you select in the menu (and meter at), but if you go by the zebras and ignore your light meter and put middle grey at 50-55 and skin tone at 60-65 you will have to protect your highlights more, but have no fear of underexposure.

Files can be viewed here and I welcome other DPs evaluation of them:

http://www.dghagey.com/Director_of_Photography/Red.html

[Álex Montoya]

Very educative, Gregorios. If the noise floor is indeed improved in the newer firmwares, underexposing a bit looks like indeed the best option.

[Graeme Nattress]

As far as I can see, your Stouffer test shows a very log scale, and there is no knee, so I don't know what you're talking about on your chart there. When I take the log of your linear output, I get a straight line, which would mean to me, that the data is linear light and that the stouffer is log, which is correct.

See graphs (yours top, my Stouffer bottom for comparison):
1985

Graeme

[Gregor Hagey]

I only know how to use a waveform and vectorscope to analyse video and the steps do not progress in a linear fashion at the knee and toe. I consider the dynamic range to begin with the first visible step on the waveform and end with the last step where the video clips.

[Graeme Nattress]

Linear light is just that - linear - if you were to put in twice the intensity of light, you'd get a number twice as big. But stops are powers of two - each stop more gives twice the light, so you add 1 stop, but double the light - which is why you get the curve you see - each three steps gets a doubling.

SO, if you take the logarithm on the data, it will plot a totally straight line as shown.

I'm not disagreeing with your measurments - as you point out we all have our own way to define DR. What I am pointing out is that there is no knee or toe in the data - it's a straight line in linear light as my graphs show. Get a copy of ImageJ - very useful for this kind of thing, and do a "log" filter on your linear light image to convert it. Now drag a line selection over your stouffer, and Analyse/plot profile from it. You should get the graph I showed above. I hope that helps!

Remember linear light export exports the image with no curve at all on it. The curve you see in the waveform is because the stouffer is not linear - it's in stops, which are logarithmic. Video is usually gamma encoded, and this is often referred to as "linear", but that's wrong, and bad terminology. It's used because it makes mathematically data "perceptually linear", but that's not a straight line, and of course, linear means a straight line.

So, with linear light data, take a log, plot it - you do get a straight line, as we should for a stop wedge under linear light export.

Graeme

[Rudi Herbert]

Gregorios,

Thanks for the detailed report. What are your impressions regarding noise patterns? There's another thread somewhere in the forum where a few users and owners agree that their images pretty much show very bad noise at anything higher than 320 ISO, and that's worrying to me, as I plan to shoot lots of low light exteriors.

Thanks,

[David Mullen ASC]

I used to say that grain was a little like salt in your food, no one was going to agree on the proper amount, it was a matter of taste.

Noise is similar -- there is more noise at higher ASA ratings, or with more underexposure, but you'd have to test to determine when it was objectionable for the material you were shooting, and that would also depend on the project's visual needs (dramatically, commercially, etc.) -- and on the planned viewing environment / distribution.

Plus don't forget that for both film and digital, there are noise/grain reduction software. A small amount of noise reduction may be just enough to allow you to use enough underexposure for your particular project.

[Gregor Hagey]

Linear light is just that - linear - if you were to put in twice the intensity of light, you'd get a number twice as big. But stops are powers of two - each stop more gives twice the light, so you add 1 stop, but double the light - which is why you get the curve you see - each three steps gets a doubling.

I just re-exported the stouffer as a linear light (the other waveform example was REC 709) and what you say is true, each step doubles in height from the last until it clips. What has me confused is that I usually treat a 10 unit change in height as a doubling in light or a 1 stop change (this doesn't always hold true in the real world, but usually). If each step of the stouffer is a 1/3 stop change in brightness, shouldn't 3 steps line up with each 10 units?

I use Ansel Adams definition of dynamic range "...the first useful values above Zone 0 and below Zone X, or Zones I to IX. The range of zones which convey definite qualities of texture and the recognition of substance is the textural range, from Zones II to VIII." I see Zone 0 as 0 units and Zone X as 100 units. Clearly there's room for interpretation with this definition, but I see at best 24-27 steps of dynamic range. I don't know why this should be considered anything but a fantastic latitude. I've never had this range with any other video camera.

[Gregor Hagey]

What are your impressions regarding noise patterns? There's another thread somewhere in the forum where a few users and owners agree that their images pretty much show very bad noise at anything higher than 320 ISO, and that's worrying to me, as I plan to shoot lots of low light exteriors.

Thanks,


I agree with David.

[jbeale]

Files can be viewed here and I welcome other DPs evaluation of them: http://www.dghagey.com/Director_of_Photography/Red.html

Wow! I read Reduser quite a bit and had not previously discovered this treasure trove of test data- was it announced before and I just missed it? At any rate, thanks for putting all this online, there's enough here to spend quite a few days looking at. I am curious about the resolution test images, for example http://www.dghagey.com/Director_of_Photography/Lens_Resolution_files/24-S4-75-F5.6.tiff

looking at the center, I see some rather noticeable blue-orange color aliasing. Of course the high contrast chart is sort of a worst-case example, but do you think the anti-alias filter should be stronger?

http://www.bealecorner.com/D30/misc/RED-24-S4-75-F5.6-crop.png

[Graeme Nattress]

I've never seen nasties like that in my 4k zone plate tests, which I think stress the situation to a greater extent than that sharpness chart. I'd need to see the R3D file though. Also, which version of RedAlert was it converted on, as the demosaic has been improved along the way, especially to deal with such issues. To me, looking at the image, it's on an older demosaic than is current, but even for me, it's hard to tell just looking at the pixels. If it's an older REDCINE, then again, newer code which is in sync with REDAlert is much nicer on the red and blue channels.

I feel the OLPF is about right. The extensive aliasing tests I did have always shown very well balanced results - balanced between aliasing and resolution.

Gregor, if you wouldn't mind helping me out on this with a R3D from that resolution shot, it'd be appreciated!

Graeme

[Graeme Nattress]

I use Ansel Adams definition of dynamic range "...the first useful values above Zone 0 and below Zone X, or Zones I to IX. The range of zones which convey definite qualities of texture and the recognition of substance is the textural range, from Zones II to VIII." I see Zone 0 as 0 units and Zone X as 100 units. Clearly there's room for interpretation with this definition, but I see at best 24-27 steps of dynamic range. I don't know why this should be considered anything but a fantastic latitude. I've never had this range with any other video camera.

I'm not disagreeing with you at all on this! You're just using a different definition than I am - that's all. That's the thing with DR - we each have our own definition.

I think we can do better than what you saw though - I looked at your stouffer a lot to generate the graphs I've shown, and it didn't seem to extend as far into the shadows as I'd have liked. I pulled up one of my reference stouffers and put it together with yours in Photoshop and it seemed better by a fair bit. Testing DR this way is mighty tricky though, and a lot of factors are involved. Thanks for sharing with us all though, and for the discussion! It prompted me to come up with those new graphs, which I think are pretty interesting, so thanks for that.

Graeme

[Gregor Hagey]

Gregor, if you wouldn't mind helping me out on this with a R3D from that resolution shot, it'd be appreciated!

Graeme

Can you PM me where to upload the .r3d? I always use Red Alert for exporting tiffs. It would have been the newest version available the week of October 22.

[Daniel Meador]

ok. This question is so basic I am embarrassed to ask. But I have to know anyway. How does HD look on a cinema screen? Can you even project it with a 2K digital projector? Is it practical to spend the extra thousands and wait and wait for a RED SCARLET 3K compared to just buying a Sony PMR EX3 now? My ambition is to screen a film at a film festival. Is HD 'good enough'? And if it can be done what about the 'look'. Audiences are used to seeing film. It's not a 'theatrical movie' in alot of peoples minds unless they see that film look. I mean, people watch video all day long at home on TV. But when they shovel over money they want something different. Film is beautiful if in the right hands. Audiences see it. And what about all the glare and blown out bits video produces. I submit 'Knowing' and 'District 9' as examples. Red digital, Sony, etc............it's all CMOS sensors isn't it?. Now I understnad content is king. The academy award went to a film shot 2k digital.

Jannard has made alot of claims so far about the amazing progress he is making. Of course we are all waiting to see it. All we know now is that the hardware is pleasingly estetic Do I wait and take it all on faith? I'd like to know what a professional cinematographer such as Mr. Mullins thinks as well. It's hard to ride this wave of bleeding edge digital technology for months on end. I want to make ART now. But I don't want to waste money on an HD camera or for that matter 'todays technology' ie RED ONE, if on the near horizon is the SECOND COMING. Know what I mean?

[geoffboyle]

I missed this thread when I originally posted about the Hannover tests.

I continue to test the way that I've always tested as this gives me the chance to compare tests from now with those of 25 years ago, yes I have been testing longer than that.

I have put examples of all the tests on the CML website, you don't have to be a member to access any of these.

You can also be a member to get access to the members messages directly without getting ANY emails, there's an option in the user setting for web only. It's been there for 9 years.

Initially we were only email but that was '96 to '00

As long as you know how test were done, and I always detail this, you can learn a lot from them.

I haven't published any of my most recent tests yet because I have found what I consider to be inconsistencies and I'm talking to RED about this before I publish, I'm also talking to Technicolor.

I'm also looking at the effect of different de-bayering processes.

[Dan Hudgins]

looking at the center, I see some rather noticeable blue-orange color aliasing. Of course the high contrast chart is sort of a worst-case example, but do you think the anti-alias filter should be stronger?

On the center pattern there seems to be an asymmetry in the vert and horz resolution, I seem to see that in other sensors as well and have been looking into the cause.

The first thing that seems logical would be the pre-amp bandwidth before the ADC, since before they have posted sine wave charts used for adjusting the so called 3.2K resolution, if the horz resolution is lower than the vert resolution then if they adjust for the horz the vert will be peaked too much.

To compensate for that you need to blur the image in the vert to make the resolutions equal? (or use better preamps)

=

On the issue of Dynamic range, it would be good if the code for REDCINE and REDALERT would have a "optical balance" setting for their de-Bayer, that way you can get the full 12bits of dynamic range, more or less.

Because the sensor is not 100% in blanace with any standard color of light some clipping is done to balance the white clip levels for R,G, and B.

Since there is not adjustment for the clip levels that gives total fine control in REDCINE and REDALERT you need to add an option to set those clip levels at least to 100% signal, then an optical filter can be used to balance the sensor to improve the dynamic range.

This is a simple feature, and its hard to understand why it has not been included all along?

[Graeme Nattress]

On the center pattern there seems to be an asymmetry in the vert and horz resolution, I seem to see that in other sensors as well and have been looking into the cause.

The first thing that seems logical would be the pre-amp bandwidth before the ADC, since before they have posted sine wave charts used for adjusting the so called 3.2K resolution, if the horz resolution is lower than the vert resolution then if they adjust for the horz the vert will be peaked too much.

To compensate for that you need to blur the image in the vert to make the resolutions equal? (or use better preamps)


That's because the centre of that chart IS asymmetrical.

Graeme

[BradWright]

ok. This question is so basic I am embarrassed to ask. But I have to know anyway. How does HD look on a cinema screen? Can you even project it with a 2K digital projector? Is it practical to spend the extra thousands and wait and wait for a RED SCARLET 3K compared to just buying a Sony PMR EX3 now? My ambition is to screen a film at a film festival. Is HD 'good enough'? And if it can be done what about the 'look'. Audiences are used to seeing film. It's not a 'theatrical movie' in alot of peoples minds unless they see that film look. I mean, people watch video all day long at home on TV. But when they shovel over money they want something different. Film is beautiful if in the right hands. Audiences see it. And what about all the glare and blown out bits video produces. I submit 'Knowing' and 'District 9' as examples. Red digital, Sony, etc............it's all CMOS sensors isn't it?. Now I understnad content is king. The academy award went to a film shot 2k digital.

Jannard has made alot of claims so far about the amazing progress he is making. Of course we are all waiting to see it. All we know now is that the hardware is pleasingly estetic Do I wait and take it all on faith? I'd like to know what a professional cinematographer such as Mr. Mullins thinks as well. It's hard to ride this wave of bleeding edge digital technology for months on end. I want to make ART now. But I don't want to waste money on an HD camera or for that matter 'todays technology' ie RED ONE, if on the near horizon is the SECOND COMING. Know what I mean?

Paranormal Activity was shot on a cheap HD camera. Really low grade cameras have been used to shoot indie features for quite some time. People don't choose to go see a film based on what camera is used. However, shooting green screen and special effects shots benefit a great deal from using the best camera possible.

The Scarlet 2/3 will be a price performance breakthrough. It delivers the best pixel power for your money. The problem is that nobody knows when they will actually be able to get one. It could be a six month backlog from the still to be determined ship date.

Therefore, get a camera that you can use now if you can't wait six months for the Scarlet. If you can hold out, it might be worth it. However, don't put you life on hold waiting for this thing to ship.

[Jeremy Neish]

Here is a test I did with build 15:
http://redhelp.net/wiki/index.php?title=Latitude

[Dan Hudgins]

That's because the centre of that chart IS asymmetrical.

Humm?

I think their is a systemic issue with the Bayer filter, because the RED/BLUE distance is larger than the GREEN/GREEN distance if you adjust the OLPF for the GREEN/GREEN then there is not enough blur for the RED/BLUE, and if you adjust the OLPF for the RED/BLUE then you over blur the GREEN/GREEN and you need more sharpen for the GREEN or LUMA and so pick up more noise that way.

If there was a OLPF that had a smaller radius for the GREEN then RED and BLUE it might work, othersize you lose some detail trying to control the yellow/cyan artifacts, like the ones in that test chart.

I have been converting the Kinor-2K and ACAM DII DNG into RAW data files to process and notice the SAME yellow/cyan artifacts that you said newer versions of your de-Bayer code hide better.

The Kinor-2K does not seem to use an OLFP, and the OLPF in the ACAM DII seems too close to the sensor or something, they may not have noticed since they may be shoting indoors at larger f/ numbers, as everyone knows the "plate effect" varies with f/ stop, so if you shoot a test chart at f/2.8 using a Zoom indoors and adjust the OLPF then shoot outdoors at f/6.3 with a sharp wide angle lens you can get more aliasing that you did not see on the chart.

So what is the answer about the OLPF radius not matching for GREEN-GREEN vs. RED-RED or BLUE-BLUE distance?

How does software remove the yellow/cyan artifacts when that job is for the OLPF?

[Graeme Nattress]

Here's what that R3D looks like today.

As for what happens to the chroma moire - there's analysis that detects and cancels it out.

OLPF is tuned for somewhere between the needs of green and needs of chroma, but takes into account the resolution needs of green, avoidance of luma aliasing, appearance of chroma aliasing and removability of chroma aliasing. It's a fine juggling act.

Graeme

[Dan Hudgins]

As for what happens to the chroma moire - there's analysis that detects and cancels it out.

Thanks for the reply on the OLPF issues.

The edge finder for the chroma patches does the opposite, so if the "analysis" does not come out right you get speckle or blur in the wrong places...

That is not the same result as you get with a three chip camera though where each point on the image can have any chroma value independently.

At 4K or higher the small spots of color the get de-saturated may not be noticed, but the more such processing you do the less like a "simple" 3 chip RGB camera you get to, not that those are not doing signal processing now also.

When you start doing 3D LUT to "fix" IR bleed through, and "chroma key" to alter the patches of the color chart, the results may look nice, but they are not so much "photography" any longer.

[Graeme Nattress]

Photography has always been about manipulating the image one way or another...

Graeme