5.19.2020

How flat can an 8 bit, .Mov file from a Sigma fp camera get (video)? I thought I'd test it myself just to see. Click through to Vimeo to see it full screen in 4K.

https://vimeo.com/420498736


Sigma flat and otherwise from Kirk Tuck on Vimeo.

After watching the video shot with the Sigma fp in .Mov at DPR I decided to test my camera to see just how flat a file I could pull out of the camera without jumping into Cinema DNG (raw file).

I took the camera to the bridge over Lady Bird Lake in Austin, Texas and shot some tests.

I used the camera's "neutral" profile, turned down the sharpening and the contrast in the "color" parameters and then used the manual tone curves to add +4 to the shadows and -4 to the highlights for even flatter files.

All shot at 29.97, 8 bit, All-I, 4K onto a regular V90 SD card.

I used ISO 400 as it is the camera's native video ISO. I used a variable neutral density filter to adjust exposure. We were in full sun on a very bright afternoon. No fill.

I shot with the camera for about an hour in 97 degree heat, mostly in direct sun, with no heat issues from the camera.

That's all. Thanks. KT

12 comments:

Anonymous said...

I guess you meant "no heat issues"?

Malcolm said...

Hi Kirk, can you explain a bit more about flat files and why they are useful? Is it 'blank slate' on which to draw your canvas so to speak? Also, doesn't playing with the shadow and highlight sliders mean you've already moved things away from flat? Thanks.

Kirk Tuck, Photographer/Writer said...

Anonymous - now corrected. Thanks.

Robert Roaldi said...

Techy stuff aside, that's not a bad look for a post-apocalyptic "Road Warrior" type movie. I'm guessing that we'll be seeing a few films on that theme in the coming years. You'll be ready.

Michael Matthews said...

Had to look away from time to time to bring my own vision back to some baseline for “normal” color. No wonder people doing serious color grading need vectorscopes and waveforms. I have to say - on an iPad display, i’ve never seen a more detailed, well defined video image.

amolitor said...

That is an almost German level of flatness!

Also, loved the dude just pulling a u-turn in the middle of the bridge. Is that normal?

Kirk Tuck, Photographer/Writer said...

Hi Malcolm, I'll take a stab at explaining "flat video files" but it's not a working methodology I use often. It's a lot like shooting with photography files, especially when shooting in harsh sun. If the contrast is too high and the color profile's inherent contrast is too high you'll never be able to open up the shadow areas of a Jpeg file very well in post. By shooting a very flat image or video file you can go in during post processing and add more contrast to the parts of the curve that need it while keeping the contrast lower in the shadows and highlights. In a general sense it's the same with over sharpening in Jpegs; once you shoot an over sharpened file it's impossible to really go back and undo that effect. If you start with the sharpening turned down then you can add back in the sharpening you want.

In pro video cameras and many hybrid cameras you will also get a V-Log profile. This compresses the overall tonal range of a file in a very specific way which makes the entire file very flat and can have a much greater effect than just general flattening because it uses a logarithmic compression which can then be decompressed. Not all cameras have Log files for video so people working with those cameras, and shooting in 8 bit .Mov or MP4 codecs strive to compress the files by pulling down the highlights and pushing up the shadows when they shoot.

Except in situations with harsh, intense and contrasty sunlight I rarely use either Log files or super flat files like the ones I'm showing in the video. I did this experiment because Richard Butler of DPReview posted a video shot with a Sigma fp and wrote that he was unable to get a "flat enough" file. I wanted to present these files to him to see if this matched his results or if more experimentation was required. I normally shoot files as close to the "final look" as I can and control contrast via lighting or subtractive intercessions.

Anonymous said...

Thank you. Your explanation in the comments deserves study.

Anonymous said...

Would love to hear your thoughts on the ungraded colors and possible issues with grading in post. A bit of weirdness with orange? <= Stupid question? I'm an amateur.

Malcolm said...

Kirk, thanks for the explanation!

Frank Grygier said...

Video styles in most cameras offer adjustments or "paint" menus to alter the image to taste. This produces an image right out of the camera that is intended for immediate use in the editing suite with very little color correction. Thus speeding up project delivery. Using paint menus(pro video camera term) to create a flat image with the hope of increasing dynamic range distorts the gamma curves of the image profile. It is best to choose a camera that offers LOG or RAW presets to attain the best dynamic range possible from the camera's sensor. These profiles are meant to be processed in post.

Anonymous said...

Very frustrated we do not have ISO25 as with Kodachrome, or ISO3 as with Tech Pan. Great high ISO settings but we get "use a neutral density filter" instead of honest low ISO settings. I don't want ND filtration - extra glass defeats the purpose.