Weird effects on very overexposed material


(Geoff Boyle) #1

I’ve been using Resolve 15.6 to produce the mp4 files for cmltests.net and have been finding some strange things with some of the cameras, C700FF and Gemini in particular.
On the extremely overexposed shots the highlights go pink or desaturated grey. This is working from the original raw files although I did try using one of the manufacturers raw software to produce EXR’s and then load those in to Resolve but they display the same issue.

The raw files are all available from cmltests.net of you fancy a play!


(Thomas Mansencal) #2

Hi,

I haven’t looked at the images but from your description isn’t that non-recovered sensor clipped data for the former and recovered sensor clipped data for the later? It is typical when some of the channels are clipped, usually green clips first which yield magenta once converted in a working RGB space.

Cheers,

Thomas


(Nick Shaw) #3

I concur with @Thomas_Mansencal.

Because you are pulling down the overexposed images to normal, the channel clipping artefacts get pulled down out of the highlight roll off range, and made obvious. If the exposure were not compensated for, they would probably still look white through the RRT and Rec.709 ODT. The more highlight latitude a camera has, the higher the clipping point is, so the less far into the visible range it gets pulled down.


(Kevin Wheatley) #4

In raw file processing there is typically a sensor saturation control which hard clips at a given sensor exposure level, to maintain ‘neutral’ at high levels, depending on the white balance, It does sound like that is perhaps related to this situation.

Kevin


(Geoff Boyle) #5

OK, an update…
Using the updated Canon Camera RAW Developer to export to EXR in ACES and then load into Resolve in ACES works fine, everything is as it should be.
This was not the case with the previous version of CCRD.
The problem still exists if the files are directly loaded in to Resolve, this seems to be very clear evidence that Resolve has not yet been updated to deal with C700FF footage, soon?