While exploring Blender 5.2 I tried converting the colorspace of some videos from my Canon R5 Mark II (C-Log 2) into Rec.709. But either I’m doing something wrong or Blender’s C-Log 2 is completely incorrect.
I’m simply using a compositor modifier on the strip with a Convert Colorspace node. My working space and color management in Blender is sRGB + Rec.709.
I’m not sure it’s either. I’ve no personal experience with using Canon footage in Blender, but I do know that “CLog2” does not have a singular conversion solution.
Hard to say. You have the main color management settings set to raw and no look, right?
What does this mean? Display is set to sRGB and working space to Linear Rec.709, right? That should not be a problem as long as you don’t have any view transform (its set to Raw) as well as look is set to None.
No, I’m using Canon Cinema Gamut. Honestly I’d never heard of D55 until testing this stuff in Blender. I just assumed that Blender’s Canon Log 2 would convert using the Canon Cinema Gamut (or something similar) since it’s be pretty much useless to convert C-Log using anything else (as far as I understand it).
Oh, I also tried removing the compositor modifier and instead changing the strip’s source colorspace to Canon Log 2 and that seemed to keep the same contrast/gamma but gave me a different exposure. Using that method, the exposure on the darker sections looks kinda correct (I think) but anything from like high-mid+ is blown out.
That’s a problem. It’s working as it’s supposed to and you are getting incorrect results because the settings are incorrect.
Your footage is in some color space and it’s unclear what color space is set for it in Blender, so the wrong starting color space may be assumed or set for the footage. It should be set correctly. You provided no information about that, so it’s unclear.
What’s happening in the group you show:
The node group you show takes whatever unspecified input, assumes it’s CanonLog2 CinemaGamut D55.
The node group then converts whatever unspecified color space as if it was CanonLog2 CinemaGamut D55 to Linear Rec.709.
Scene color management is applied and that Linear Rec.709 is converted to sRGB using “Standard” view transform.
I assume that’s not what you want and I am guessing that you want to output Linear Rec.709 without any scene color management being applied. So you need to set the view transform to Raw if that’s the case:
That should solve the issue if you expect Linear Rec.709 if there are no other problems in whatever happens before the compositing node group you show.
I’m not sure if I might be misunderstanding what you’re saying. Let me try to fully fill in any gaps in the information I’ve given.
So the video is captured/converted to C.LOG 2 and C.GAMUT natively on the camera (I’m pretty sure this is C-Log 2 and Canon Cinema Gamut or just Cinema Gamut).
Then, when I put the video into Blender it automatically sets the Color Space of the Source as sRGB.
This gives me two options: change the source color space to CanonLog2 CinemaGamut D55 or use a compositor modifier to convert the color space from CanonLog2 CinemaGamut D55 to something (default is Working Space but I’ve tried sRGB and Linear Rec.709). Both of these options give two different results, both incorrect. I also tried doing both together but they just stack on top of each other and look really bad.
Is that the info you were after?
Also, I tried setting the Look to Raw but that’s worse than Standard (the image becomes almost completely black).
Image color space should always be set to what it actually is, so if it’s not sRGB, it should definite not be set to sRGB. If you are trying to just convert the image to working space, you don’t need to do anything at all except set the image color space to what it is. Blender automatically converts everything to its working space.
I’ve tried every different combination of color space conversions I can think of and nothing is correct. The image above is source color space as CanonLog Cinema Gamut D55 and the view as Standard. I also tried it with the view as Raw but that is also incorrect and a bit worse than Standard.
It’s really hard to advice without a very clear and exact definition of what you are doing and what the goal is.
Yes, that is absolutely what I would expect to see if I set the view transform to Raw. I thought the goal is to save it as Linear Rec.709 (raw). this is how it looks on screen as raw values.
What do you want to do? What result are you expecting? If you just want to edit the footage in Blender, then just setting the correct color space in Blender should be enough, but then you have to color grade the image for output and Standard view transform may not really be amazing choice for this. I thought you want to convert to Linear Rec.709 and export for color grading in another software or something like that.
I’m not exactly doing anything with it, I was just testing and then noticed what looked like a bug so I wanted to check if it was a bug or just me doing something wrong.
What I expected Blender to do is convert standard C-Log 2 video to standard Rec.709. I imagined this would be pretty straight forward like it is in Davinci Resolve. Import video into Rec.709 workspace/timeline > Convert video from C-Log 2 to Rec.709 within that Rec.709 workspace (refer back to my first post to see the expected result that Davinci Resolve gives). But for some reason, when Blender does the same C-Log 2 to Rec.709 inside a Rec.709 workspace, it does something completely different and what appears to be wrong.
What I do with the video isn’t exactly relevant as the color space conversion is an independent step. So whether I am editing the video in Blender or I’m exporting it out to edit in other software shouldn’t change the fact that it should properly convert C-Log 2 to Rec.709.
Standard video from most cameras is recorded in Rec.709. My Canon R5 Mark II has the option to instead record the video in C-Log 2. There is then a standard conversion from C-Log 2 to Rec.709. I expected Blender to follow this standard conversion.
As far as I know that is what is happening, everything is working correctly as far as I can tell now. You cannot really view Linear Rec.709 on a regular display though.
Might it be that “linear” is the keyword here? Rec.709 is not the same as Blender’s working space. Blender’s working space is a linear color space with Rec.709 primaries(well, we now have the other options, so if they are not selected). I suppose one could also say it’s a linear color space with sRGB primaries just as well. We could call it linear sRGB if you think about it… Anyway… Do you need to convert to Rec.709 color space and not linear color space with Rec.709 primaries that Blender’s default working color space is?.. I don’t understand why you would need this though. That’s why I am asking about the context. I don’t think I understand what you need.
We don’t have Rec.709 itself in Blender as far as I understand:
I don’t work with this, but I am puzzled, why the term “gamma” is used there. It’s probably not really just a gamma curves, Rec.709 probably has more complicated formulas just like sRGB, so they are not actual gamma curves, just misleading names, but hey it’s colormanagement, it must be like this I guess… It’s interesting to see an understand this without the actual working experience in it…
Ah, I didn’t realize Linear Rec.709 and Rec.709 weren’t the same thing. I think that Gamma 2.4 is what I’m after (that’s what I was using in Davinci paired with Rec.709). The color still looks wrong though.
I wonder if the issue though is that I can’t set my working space as Gamma 2.4+Rec.709. Because I have to keep the source color space as sRGB and then add the compositor modifier after that (from C-Log 2 to Gamma 2.4+Rec.709).
Context wise, I’m basically was just expecting to be able to convert the colors from C-Log 2+Cinema Gamut to Rec.709+Gamma 2.4 and then do additional color-grading after that (still inside Blender).
I might be able to get one a video file uploaded somewhere if you wanted to test stuff yourself.
So the way I understand it, you should still set view transform to raw and do color management in the compositor with the convert to color space node and the color space for the footage should be set to what it actually is. Are you doing it like that?
I think that makes little sense. I am not sure… Unless you are mixing footage with other footage that is already in Rec.709… But color grading should probably be done before converting to final output color space that Rec.709 Gamma 2.4 is.
OK, I don’t know what’s going on, but by my understanding, “both” is incorrect. If view transform is set to raw, then there is no color transform there.
What should be happening by my understanding is:
Footage is set to it’s color space so blender can read it. 2. it’s automatically converted to working space. 3. working space is converted to Rec.709 with Convert Colorspace node. 4. since scene view transform is set to raw, nothing happens here(as opposed to some other color transform)
Yes, although you should be able to do color grading individually for any video with any color space. The work space settings should only be for what you expect your output to be, they shouldn’t effect import color space or color-grading.
Anyway… Do you need to convert to Rec.709 color space and not linear color space with Rec.709 primaries that Blender’s default working color space is?.. I don’t understand why you would need this though. That’s why I am asking about the context. I don’t think I understand what you need. 
