ISO ratings - Dynamic range - Real world meaning

[roryhinds]

I'm unsure how to read this info about the ISO and wonder how it relates to real world practice.

The ISO 8000 shot was at F22?

What does this mean in actual low light situations say I'm shooting a candle light dinner scene.

I would be shooting wide open not at F22.

It would be great to see low light takes to gain an understanding of what the camera can do as I'm sure everyone wants to know how it performs with little to no light at night.

I'm sure test will be done by reservation holders once the camera ships but why don't RED do this test?

Am I missing something here?

[Mark L. Pederson]

I'm unsure how to read this info about the ISO and wonder how it relates to real world practice.

The ISO 8000 shot was at F22?

What does this mean in actual low light situations say I'm shooting a candle light dinner scene.

I would be shooting wide open not at F22.

It would be great to see low light takes to gain an understanding of what the camera can do as I'm sure everyone wants to know how it performs with little to no light at night.

I'm sure test will be done by reservation holders once the camera ships but why don't RED do this test?

Am I missing something here?

Rory -

This all relates to real world practice - as they are pushing the sensor to see how far you can rate the ISO and still get an acceptable image.

It clearly demonstrates the range of the sensor. And I am going to take a guess that there are a few "knobs" they are turning in the home stretch here before they crank out some production units - to get the MOST out of that sensor.

As far as your candle lit dinner scene - you may NOT shoot wide open - that all depends on what ISO you select, the footcandles, what you want to do in POST and how you want it to look (desired DOF, etc.). And that starts to get a little ... subjective.

I think RED is posting a image here and there to keep REDUSER's excited - but they have a mission critical path to make this camera the best it can be and get it shipped to reservation holders.

If they started posting every test that every DP and REDUSER wanted to see - we'd never get our cameras.

I can assure you that the first folks with the cameras will not be too shy about showing the world images shot on RED cameras.

I've shot candle lit dinners in HD before - looking at that image rated at 8000 ... I'd have to say NO WORRIES, RORY it's gonna look fantastic!!

[Graeme Nattress]

What it means, is that, all things being equal, you can under-expose a shot by 5 stops (8000ISO to 250ISO is 5 stops) and "get away with it".

Graeme

[David Mullen ASC]

You have to think of ND filters and f-stops controlling the amount of light that hits the sensor -- the sensor itself doesn't care how much light was in front of a lens and camera, only how much light it gets.

So shooting under a lot of light and stopping down to f/22 versus shooting in very low light and opening up to f/2 can mean that either method produces the same light level hitting the sensor. The only real difference is with depth of field.

So in this case, stopping down to f/22 reduced the amount of light hitting the sensor to levels low enough to be similar to actually shooting in very low light levels with a wide-open stop. And since a color chart doesn't have any self-illuminating properties, like a candle does, it doesn't really matter which method you use to reduce the amount of light. A candle shot at f/2 versus f/22 will look very different; a chart lit to f/22 versus lit to f/2 will look the same except for depth of field.

[Charles Angus]

While I totally agree about charts, I have found in some big features they overlight the night scenes and compensate with ND, which doesn't look the same.

I remember a shot in "The Pianist" where the "moonlight" is shining right through Adrian Brody's nose - obviously a big HMI not too far away... That's an extreme case, but it also effects the apparent ambient level of illumination, I find.

Charles

[roryhinds]

I guess will just need to wait till we get the camera to do real world low light tests.

[Gavin Greenwalt]

It also means if you want the DOF of a 1/3" Consumer camera it's theoretically possible without lighting your cast on fire.

[Júlio Taubkin]

It also means you can shoot availiable light night scenes with an incredibly affordable, but not incredibly bright F2.8 zoom lense, wich is perfect for documentary setups, including the easier focus than shooting with an expensive F1.3 prime.

[Michael Brennan]

And the reason the chart isnt lit by a candle or by incandescent bulb at very low level, is that isn't that easy to get even illumination and consistant colour temperature at very low light levels, easier just to stop down!

For instance spill or bounce light from the viewfiner can hit the chart and worklights would have to be turned off, leaving the operator fumbing in the dark.

I wonder if DSC labs can make a low light version of their rear illuminated chart especially for this kind of test?


Mike Brennan

[Shawn Nelson]

Continuing on taubkin's thought...this means that the Red zoom will be plenty to shoot night stuff with! Which is very, very nice for those of us that want to do a ton of night stuff without the expense of super primes or expecting an AC to pull focus at under T2!

[Steve Gibby]

Continuing on taubkin's thought...this means that the Red zoom will be plenty to shoot night stuff with! Which is very, very nice for those of us that want to do a ton of night stuff without the expense of super primes or expecting an AC to pull focus at under T2!

To build on that, Jim mentioned on another thread that the ISO tests were shot using the RED 18-50 CF zoom and a 65mm Cooke prime. The sensitivity of the Mysterium sensor could make the RED zooms a very attractive choice. The RED lenses are made for use with the Mysterium sensor.

[Stephen Williams]

expecting an AC to pull focus at under T2!

Hi Shawn,

An experienced AC should be able to pull focus wide open, thats just part of the job. I actually prefer the bokeh of many lenses when wide open.

Stephen

[Shawn Nelson]

Stephen, this is true, in theory. Have you read David Mullen's journals? He works with pro ACs (more pro than I can score) and he prefers to be at least at f4 due to this reason.

[Stephen Williams]

Stephen, this is true, in theory. Have you read David Mullen's journals? He works with pro ACs (more pro than I can score) and he prefers to be at least at f4 due to this reason.

Hi Shawn,

I don't think David has ever shot with Cooke S4's, they have a very soft roll off wide open @T2. True T4 makes life very easy, however a night shot 'stopped down' looks like ugly day for night so it may not be the best solution.

Both David & I have worked with focus pullers, that were not as skilled as they should be!

Stephen

[Warren Kommers]

Hi Shawn,

An experienced AC should be able to pull focus wide open, thats just part of the job. I actually prefer the bokeh of many lenses when wide open.

Stephen

This is the wrong thread for this discussion but.

Wide open, 2 or even 1.3, is a look that can be ideal at times to tell the story. It's a very intimate look. However, you have to weigh the advantages and disadvantages. Most of the time the disads out weight the advantages I find. In my opinion that look and intimate feeling isn't going to me mean shit if the actors eyes are out of focus, even in the slightist. Immediately the audience is out of the story. You might as well have a scratch on the film. It is risky and somtimes selfish choice by the DP. Let me explain.

I've seen AC's loose their job by the will of the producer for "soft" dailies when clearly the DP has put them in a nearly impossible position focus wise. He will be the fall guy before the DP. This has not happened to my guys yet but it can be a moral question you have to ask yourself as a professional. There is a shit ton of expensive stuff happening in front of your lens, from Tom Cruise's face to the building blowing up that you are resposible for capturing. In focus.

There is a point where even the most experienced AC won't be able to get it. Watch Transformers for example. Many soft difficult shots. But oh wait...those AC's were probably just out of film school pulling anamorphic C series. Probably not the best out there. Not likely.

[David Mullen ASC]

When you're shooting five pages a day, thirty set-ups per day or so, you're moving pretty fast, so I don't like to make the focus puller's job unnecessarily difficult unless I have a good reason (like shooting under candlelight, etc.)

If you're lighting a house for moonlight, there's no reason to light it to an f/1.4 when you can light it just as easily to an f/2.8 probably -- unless someone is carrying a candle in the scene. Otherwise, I've never understood the reason why some DP's, when they have a decent lighting package, light a room to f/1.4 unless they are balancing with something self-illuminating with limited intensity (again, candles, or flashlights, distant city lights, etc.) Someone lit from the side with a blue-gelled inky at f/1.4 is going to look the same if you used a 1K instead to get an f/2.8, and you're going to have a much better probability of nailing the focus if the director decides to put a 100mm on and follow the actor around in a C.U.

That said, my journals in which I said I tried to light for at least an f/4 was for my 35mm anamorphic shows -- f/4 in anamorphic is almost like f/2 in spherical in terms of depth of field. For spherical, I tend to prefer an f/2.8 or f/2.8-4 split (in case I have to use a T/3 zoom). Unless I'm doing a night exterior and need to capture more natural ambience.

[Paul Hazlett]

For anyone that has a video background and not used to using iso ratings
here is a link to basic explanation of iso and exposure.

http://www.eyetec.net/group5/M21S1.htm

hope this helps.

[Stephen Williams]

Someone lit from the side with a blue-gelled inky at f/1.4 is going to look the same if you used a 1K instead to get an f/2.8, and you're going to have a much better probability of nailing the focus if the director decides to put a 100mm on and follow the actor around in a C.U.


Hi David,

Interesting enough last week I was using an 800w Joker bug as a back lit key, I tried a bigger source, it just did not look the same. First time I ever used a Joker Bug, it wont be the last!

Stephen

[Michael Brennan]

Hi David,

Interesting enough last week I was using an 800w Joker bug as a back lit key, I tried a bigger source, it just did not look the same. First time I ever used a Joker Bug, it wont be the last!

Stephen

For those Red users on a budget a joker is a very versatile lamp. The 200w Joker Bug can be used upside down to give effect of a domestic bulb.

I have both 800w and 200w, I used the 200w in India to light a moonlit courtyard scene where there was precious little power, where we strung it over the courtyard from balcony to balcony with rope. Used every single watt of its 200w output!


Also adapted aluminium domestic open face haging fixtures to the bug, so that it can hang into shot.


Also works strung between two palm trees.




Mike Brennan

[Júlio Taubkin]

Hi Shawn,

An experienced AC should be able to pull focus wide open, thats just part of the job. I actually prefer the bokeh of many lenses when wide open.

Stephen

The great thing is that the RED camera never denied us the possibility. Just rent a fast lense, and use some neutral density and we're set.

I was just excited because although I love to shoot fiction work, I earn my living shooting docs, mostly without competent 1st ACs, and sometimes in very uncorfortable places where they wouldn't even fit (like in the back of a volkswagen)...
:tongue: