That said...IF you wanted to use a full and proper calibration process (which in some circumstances may be required...even with it's low dark current, during the summer with an uncooled camera, it could still be problematic enough to require dark calibration; vignetting could be bad enough to require flat calibration in some situations), then black clipping would pose a problem. For that matter, so would any kind of SLog as well.
Why? Because for bias and dark subtraction and flat division to work, the signal has to be truly linear. Any non-linear processing to any of those frames before calibration occurs will render the calibration incorrect at the very least, and useless or even damaging at worst. Black clipping will mess that up, although again, I would like to know how much the black point is actually clipped, as if it is only clipped a small amount, it might not be totally damaging (or it might be totally damaging, just depends on what the offset is, and if the offset is fixed or dynamic.) I think SLog is probably worse than black point clipping though, as that by design renders the signal totally non-linear.......
FWIW, in video, any log-like SLOG2/SLOG3 is only meant to be a container for the imaged colorspace information that is more than any display can show including the dynamic range.
One can use Davinci Resolve and the ACES colorspace workflow, that allows one to work with the information in a total linear fashion.
However, the final data must have a LUT (look up table) applied to it so it will render into the limited gamut displays have to show the image/video.
Given, there is the assumption that RAW is linear.
However, even if Sony "cooks" their ARW with a curve to package the colorspace and dynamic range (that no display can fully render),
I would think it is then converted to a linear form to be processed before it is "stretched" as you AP'ers call it?
Can someone address if the ARW cannot be rendered to a linear form?
I do think there is a problem trying to look at a rendered image on a display and decide whether the blacks are clipped since the gamut necessarily has to be shaped into the gamut your display needs to render the image, and therefore is already altered.
Please watch this video (start at 2:00) to understand the value of log demonstrated:
Something I've noticed with the a7s [No one has ever mentioned this]
In the Picture Profiles
Black level, Gamma, Knee, Mode, Auto Set, Color Mode, Saturation, Color Phase, Color Depth, Detail can be changed.
Black level, Black Gamma, Knee, Color Depth do not apply with RAW.
Obviously most we set to off, etc.
But could there be an adjustment that changes some of what is discussed?
Could you set a picture profile (most things off) but change the detail setting for your RAW stills and have different results?
If someone is smart about this and can speak to this, please help inform me?
Edited by t_image, 28 October 2015 - 10:32 PM.