The math of Lumetri's operators make it mostly unusable for log grading. Most of them behave linear but use curves/rolloffs and are limited to 0-1 float when you go in their opposite direction value wise.
In a more ideal world, to me, Lumetri would always have operators that fit log grading.
- Exposure should be offset math, so it's behaves as camera exposure when applied to log footage.
- Contrast should be linear instead of s-curve in both directions.
- Blacks slider should not create a toe when lifted and inverse toe when lowered. Should act as 'lift' math.
- Whites is fine as is.
- RGB Curves should also have it's end points act as lift and gain without clip 0-1 just like the seperate Curves effect.
- 3way color wheels should be Lift Gamma Gain math instead of curve Shadow/Mid/Highlights.
None of the above mentioned controls should clip 0-1 float.
Because this would completely break video grades perhaps it's an idea to have a mode switch for Lumetri.
By default it would be 'video' with an alternative 'log' mode.