RED SERIES - PART 3
Friday, October 9, 2009 at 12:56AM GO RAW
When the Red was first announced, one of the biggest breakthroughs it proposed was the ability to deliver RAW, uncolored-corrected, “nothing-baked-in”, images directly off the sensor ( much the same way a DSLR works ). This remains one of the most powerful tools in the Red arsenal and one of the things ( along with a 35mm sized sensor ) that separates it from a traditional video camera.
But it created an unforseen problem ; if you don't know what you're looking at, raw images can be scary. Raw looks very very very flat in its uncorrected state. It can be hard to look at on set, especially for someone who has to make critical decision about other things than exposure ( like production design ). So Red included preview LUTs, ways of non-destructively previewing the corrected image in different ways. I don't blame people for wanting to look at something other than RAW on a day to day basis. With one caveat : the knowledge that those preview LUTs are going to be thrown away.
Over time, some confusion has gathered about this. Some people are starting to light and finish their projects with one of these preview LUTs baked in, especially REDSPACE. This takes away one of the most powerful features of the Red and closes the gap between it and a video camera. My respectful suggestion : Shoot RAW, post RAW. Here's why :
( These images are from the film Two Birds, shot by Chapin Hall )
RAW ( w/ 2.2 gamma )
This is what the camera saw on the day of photography, with 2.2 gamma applied to make it viewable. You can see that the sensor was properly exposed, nothing is clipped or crushed.
GRADED FINAL
The DP wanted to achieve a naturalistic, somewhat low-con look for the film, this is where we took it in the DI.
REDSPACE
This is what the DP would have seen on the exact same image if, on-set, he had looked at it through REDSPACE. Notice how much brighter, more contrasty and more saturated it is than what we ended up doing in the DI. If all I saw was this on-set, I'd be worried. I would feel that we were over-exposed and that we had missed the mark on the intended low-con, naturalistic look. In reality, there was nothing wrong with the image, it was only the distortion REDSPACE was adding that didn't actually exist in the negative.
Here's a different scenario, same principle :
RAW ( w/ 2.2 gamma )
This is what the camera actually recorded, again with 2.2 gamma applied to make it viewable. Notice how red it is. This is another important point. By looking at the RAW on-set, the DP could see exactly how the sonsor was interpreting the color temp of his light. Fortunately, this was intentional :
GRADED FINAL
The DP intended this scene to have a kind of straw, yellowish cast. This image came out as expected.
REDSPACE
But if he had been solely monitoring REDSPACE on-set and had baked-in REDSPACE in post, we would have thought that the look went way too far and would have had a difficult time pulling it back in the DI. Again, this is not an accurate representation of what was shot.
I realize you have to look at something on-set. If RAW is too confusing to the crew, try REDSPACE or one of the other LUTs, knowing that it is not an accurate representation of the image that you are shooting or what is going to come down the line in final color. Also, I strongly urge you not to “bake-in” any color space conversion into your footage before color correction. It will severely limit what you can do in the DI. In our experience, footage the is lit under RAW and graded from the RAW negative, tends to be much more organic, naturalistic, and film-like. You will be happier with the images at the end of the day.
One last note. A few people brought it to my attention that my "RAW" images are being viewed on-set and in our DI in 2.2 gamma. They are correct. The red and our Scratch add a 2.2 gamma curve to the "RAW" funciton to make it easier to see all the information. "What the camera actually saw" is too dark without a 2.2 gamma curve to be able to determine anything about. We still feel that this is a more accurate and informative way to look at what the sensor recorded than any other option.
RED SERIES 
Reader Comments (6)
Actually the sensor captures a linear image, which will appear very dark and contrasty in your computer screen. What you call RAW actually looks more like a rec709 or redlog curve applied to the footage and it´s not what the camera actually recorded. Just my 2 cents.
It seems that Scratch is adding a gamma correction of 2.2 to the RED-RAW Image (= DisplayLUT ?) like the Camera does in "Raw" viewing mode.
Have a look here:
http://provideocoalition.com/index.php/Awilt/story/quick_look_red_build_16/
Take one of the images and make a gammacorrection of 0.45 and the images more look like true linear RED-RAW from the Sensor (Reference: RED-Alert) .
You are right, Redspace adds a very harsh Gamma-Curve to the image:
http://provideocoalition.com/index.php/apple/story/redfcp_prores_clips_from_log_and_transfer/
Great Post...
After consulting with Assimilate, it turns out you're right. We allow Scratch to add a 2.2 gamma curve to RAW to make it viewable. You're right, its different than what the camera actually saw, we can't actually view that in any way that would be helpful.
I still maintain that RAW w/ 2.2 gamma tells you the most about the RAW file, and is the most useful. Also, this article is more a warning about not lighting and baking in REDSPACE.
Thanks for the input, very valuable.
You can easily see the linear image in redcine. Just press COLOR to see the raw.
It´s interesting to know that Scratch applies a 2.2 gamma curve now. Until the last update R3Ds loaded as linear with no gamma compensation until you applied a LUT or curve to the grading. I guess they went the Iridas way too.
@macgregor
If the camera captures a huge amount of data, the curve/space that shows most of it wouldn't be the one to be called "what the camera really sees"? Since RAW is non-viewable and needs interpreation anyway.
Just for "intuitive-ness" sake.
Pietro,
Macgregor is right, its technically a misnomer to say "what the camera actually sees". But You have to view that RAW somehow, so again, its a matter of personal preference. At Local Hero, we feel that this is the best way to judge the RAW, in a way that tels you the most about "what the camera actually saw" and its the way that the RED does it, too, when you hit RAW on the camera.