Canon R5 C-Log: Internal MP4 vs External Pro Res 422 HQ

Happy new year everyone,

I was wondering if anyone could help me with a question about Canon R5 and C-log.

Up until now I've been happily shooting C-log on my R5 and got a nice workflow in place for exposure and grading. Part of that workflow is using a Canon technical LUT to go from C-Log to Rec 709. The LUT is direct form Canon and has this name:

BT709_CanonLog-to-BT709_WideDR_65_FN_Ver.1.1.cube

Recently though, I got hold of an Atomos Ninja V+. I'm getting set up to shoot externally and I know I'm going to be using it mainly in UHD(4K) Pro Res 422 HQ mode. All working well but I just tried a test and found the footage looks different to the internally recorded MP4 I'm used to grading. The Pro Res shots recorded by the Ninja seem to have more contrast already and adding my REC709 LUT makes it much heavier and more contrasty than I'm used to. Whereas the MP4s look a lot flatter and greyer until they get the Rec 709 LUT on them.

The only settings I can see on the Ninja V+ which might be relevant are are in the INPUT settings. At the bottom are Camera Output settings as follows:

Log/HDR: On
Camera: Canon
Gamma: Canon Log
Gamut: Rec 709
There is a warning to "Match camera for correct image processing", so checking on the R5 Canon Log settings menu, I've got the following settings:
Canon Log: On (C.Log)
View Assist: Off
Colour Matrix: Neutral
Characteristics: 0,0,0
Colour Space: BT.709

- Any ideas why the footage doesn't look the same?
- Is there a special ProRes 422 HQ Clog to Rec 709 technical LUT I should be using for this?
- Or are my settings wrong somewhere?

Any help appreciated!
Thanks,
Thom

What video editing program are you using?

It might be that your editor is operating in a color managed mode and automatically applying the correct LUT when you input the clip and then you're applying it a second time.

I use DaVinci Resolve and went through this when I got a Z9 a year ago and first started dealing with log and raw clips.

Cheers!

Hi

I had the same issue recording Log footage onto my Ninja V with the EOS R. It's a question of different LUTS being applied and having to burrow into the Ninja V settings to correct this.

From your settings, it looks like you are viewing the footage on your Ninja V with the default Canon Log LUT. You can upload the bespoke LUT you are using for your EOS R5 onto the Ninja V via the hard drive and your PC, then set the Ninja to use this LUT. There are videos on how to do this on YouTube - see https://www.youtube.com/watch?v=EnY0YrpIs7Y

There may be a slight remaining difference between your camera LCD and the Ninja V. The Ninja V is brighter by default. You can tweak the brightness levels to suit. The best way to do this would be to shoot a test chart, or a piece of white paper, set the white balance manually so it's correct, and adjust the brightness between the Ninja V and your camera monitor so they look the same.

Hope this helps,

Erick

Hi Thom

No problem. You've made a good first start on downloading the LUT, which is a tricky operation! There is also confusingly a separate monitoring option for displaying footage with and without a LUT applied on the Ninja V. When you view the Log footage in an editor like Da Vinci resolve, you will also be to tick or untick the box under "Image" which says "Apply LUT". The LUT itself isn't actually encoded into the footage, but is associated with the footage via a side file.

Try page 32 of the Ninja V manual on https://downloads.atomos.com/ninja-v/NinjaV-UserManual01-NOV2018.pdf for more info on how to record and view footage with and without LUTS applied.

Best wishes

Erick

Hi Thom, glad to hear you are making progress! I'm not sure what button to press for turning off the LUT in Premiere Pro, but I'm sure there will be option somewhere. In Resolve its under Image settings, as "Apply LUT" tick Yes or No.

Hi everyone,

I've found the answer and wanted to report back.

The issue is caused by settings in the Atomos Ninja V+. The same applies to the Ninja V model.

Counter-intuitively, the Input > Camera Output settings on the monitor should be set as follows:

Log/HDR - OFF

Camera - Standard

Gamma - Rec.709

Gamut - Rec.709

Legalize - ON

HDR Auto - OFF

These settings bypass the monitor's automatic image processing which embeds a Rec.709 LUT into your footage with the aim of speeding up your post production workflow. You will now be recording unprocessed LOG footage which matches the internally recorded footage.

More detail can be found in this video:

https://www.4kshooters.net/2020/04/08/how-to-properly-set-up-your-ninja-v/