@C_joerg
Interesting, so black level changes happen on more canon cameras.
Not sure if I understand the stuff discussed in the links you send.
So am I right that one theory is that the camera actually uses a lower iso then it actually reports ?
So in case of the Canon R5, which only has black levels of 512 in iso 100 and 200, you think it actually uses a lower iso/gain, like 25 or 12.5 ?
Iso/gain is the only thing they can use, a faster shutter speed or smaller aperture would both be noticed by people I guess.
The 10 bit and 12 bit raw recording is possible on the 6d with raw video recording in magic lantern raw.
This was done by using a register that act as digital gain, it pushes the values recorded 2 or 4 stops lower.
Now I think about it, that makes sense that in this case the black level becomes lower in value.
Digital negative gain also lowers the noise signal, so this means lower black level
What I also see discussed in the links you send, is that the image data is rescaled in the raw files in camera.
This is also the case with the R5, max white value is always at 16383 - black level.
This makes it difficult to see what is going on...
The whole iso magic is also happening with clog1, clog3, highlight tone priority etc.
Minimum iso that is possible in 8k raw:
No log -> iso 100
Highlight tone priority enabled -> iso 200
Log1 -> iso 400
Log3 -> iso 800
When actually using the above settings and iso, and load the files in raw digger, you can see in the noise level that it's all the same, it's all recorded in iso 100
