Hi, when I was producing the samples for this post (Scene-referred editing with OCIO enabled software - #43) I considered using Luminance instead of dcraw, expecting to be able to produce a scene-referred EXR from the RAW straight away.
The result wasn’t what I expected, as the output of the RAW development and HDR generation from one single shot seemed to produce a LDR rendering.
Furthermore, the resulting EXR seems to have a 2.2 gamma applied, which is completely unexpected.
I went through the settings and documentation but I couldn’t find anything to clarify this. Am I missing something? Is it possible to produce an HDR image from a single RAW shot?
Thanks in advance.
To be able to scale the dynamic range to the captured range.
If my camera grabs 8-10 stops of dynamic range in the raw file, I’d expect to be able to take those stops to a linear scene-referred EXR.
I think I know what you mean, and of course I wouldn’t expect values beyond the sensor maximum, but that information has to be scaled afterwards I think.
As I said above. if my camera captures 10 stops it doesn’t feel right that I get the dynamic range of a jpeg in my EXR.
Oh, and I wouldn’t expect gamma correction on the EXR either, btw.
*) I’m probably requesting for a feature in the case of the scaling, but the gamma correction seems like a bug.
At the risk of telling people what they already know: dcraw can be told not to apply a gamma (with “-g 1 1”) and can be told to write 16-bit integers instead of 8.
I would hope the same is true of libraw. But I don’t know.
I suspect that that is the problem I facing. Odd that nobody complained about it yet as the convention for EXRs is linear transfer.
I just checked with Blender and Fusion and both the EXR produced from a single shot and the EXR produced from bracketed exposures in RAW format, end up being non-linear.