Canon MXF Files are clipping / are misinterpreted

Hi

we encountered a big problem with the interpretation of Canon MXF Files (From C700, C300 Cameras).

Canon gives the option to use various C-Log curves. C-Log 3 uses the full spectrum of the file.

Meaning, 100 percent brightness of the camera/sensor is also 100% brightness in the file.

Unfortunately Premiere's interpretation is too contrasty, levels are cut off on both ends. Lows are not clipped, as they're quite above 0. But it clips bright areas. Interestingly, it is possible to recover that information with Lumetri, suggesting that it is an interpretation issue. Comparing the waveform/gamma of a clip in premiere to resolve reveals the difference.

Our Workflow is editing in Premiere and grading in resolve, for that we rely on preserving all information from file to exported edit. If premiere clips shots even without any adjustment done on the timeline it's impossible to recover later on.

thanks for looking into this - it is very very important.

Tested on Premiere 2017 and 2018.1 (January Update), with both, C300mk2 and C700 Footage, on multiple systems.

When talking to friends in the field, they suggested that the C300mk2 has more dynamic range with C-Log2 compared to C-Log3. But thats not the case, It very likely just because C-Log3 is clipped in Premiere and C-Log2 leaves more headroom as 100% in Camera is only about 90% in the File.

Thanks,

K