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style="margin-bottom: 0"> RED & Sodium Vapor

Published : 27th July 2009


So, the recent conversation about RED's native colour temp. rating, and David's mention of Sodium streetlamps on the night exterior thread, got me wondering.


I know what I can get away with when it comes to Sodium street lights on an F900, and on film... Haven't tried it with a RED yet. It seems to me that it would have to be much more difficult than an HD camera with a 3200K sensor... or tungsten film... Any real-world experiences out there?

George Hupka
Director/DP, Downstream Pictures
Saskatoon, Canada
Listmum, Cinematography Mailing List



Any real-world experiences out there?


The Fellows at AFI shot some CT tests with the EX3 and discovered there is a significant difference in resolution when shooting daylight. The camera appears to be Tungsten balanced. The ones going out to shoot that weeks production all changed their approach to use #85s on daylight balanced sets/locations.


Mark Woods
Director of Photography
Pasadena, California
www.markwoods.com



>>The Fellows at AFI shot some CT tests with the EX3 and discovered there is a significant difference in >>resolution when shooting daylight. The camera appears to be Tungsten balanced.


AFAIK, all electronic cameras are "tungsten balanced" with the exception of RED, which seems to prefer daylight.


And with all due respect to the AFI, I find it extremely difficult to believe that there is any difference in resolution based on color temperature.


What I can imagine is that they took the camera outside without sufficient ND's, and irised the lens WAY down, which will indeed lower ANY camera's resolution eventually. I don't believe that for the same stop, tungsten or daylight make any difference to any camera's resolution.


>>The ones going out to shoot that weeks production all changed their approach to use #85s on >>daylight balanced sets/locations.

Since that's been the standard, more or less, for the last century, I see nothing wrong with that. With the exception of the RED, which seems to REALLY want daylight temperatures, shooting most electronic cameras outside without 85 filters just makes more work for post, and bringing up the red gain to bring the colors back into line will result in noisy reds in general, and noisy flesh tones in particular, despite what you might read here and elsewhere.


Bob Kertesz
BlueScreen LLC
Hollywood, California



Hello Bob,


With all due respect, although the Fellows designed and shot the test, I observed and offered suggestions when needed. The test and it was very methodical. Both of the shots were of the same scene, one lit with Tungsten and relit with HMIs. The stops on the lens were within 1/2 stop of each other. We viewed the scene from the flash card 2K projected on a screen.


AFI is not a film school, but a conservatory. The ASC is well represented by the faculty.


Mark Woods
Director of Photography
Pasadena, California
www.markwoods.com



>>AFAIK, all electronic cameras are "tungsten balanced" with the exception of RED, which seems to prefer >>daylight.


The Phantom used to be happiest in a daylight world, though some of them (depending on where you get them, how old they are, etc) now have a OLPF/IR sandwich that lowers the effective "native" white balance somewhat... I am a few thousand miles from my Phanom bible, but 4000k or 4200k rings a bell.


Mark H. Weingartner
LA-based VFX DP/Supervisor



>>With all due respect, although the Fellows designed and shot the test, I observed and offered >>suggestions when needed. The test and it was very methodical. Both of the shots were of the same >>scene, one lit with Tungsten and relit with HMIs. The stops on the lens were within 1/2 stop of each other. >>We viewed the scene from the flash card 2K projected on a screen.


Without knowing the full methodology and seeing the results of the test, I obviously can't comment further, except to say that assuming all the technical aspects of the shoot were done correctly, I can't think of a cogent technical explanation for what you saw.


Bob Kertesz
BlueScreen LLC
Hollywood, California



>>I can't think of a cogent technical explanation for what you saw.


Hello Bob,


The whole Cinematography class saw the difference and Bob Primes was in the theatre with us, and it surprised him. He owned an EX1 and now has an EX3 that he's used extensively. Tim's link to contrast and color was very interesting. I suggested the test to the class since they had read and seen my presentation of the Thompson White Paper regarding Color Temperature and the use of a Magenta filter to expand the dynamic range and also clean up the green fringing that can happen when the sensor reaches saturation (i.e., clips).


As I learn more, I will post.


Mark Woods
Director of Photography
Pasadena, California
www.markwoods.com


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