In libraw_colordata_t, there is a variable called FujiExpoMidPointShift. I couldn't find any documentation about it. FujiExpoMidPointShift seems to contain the "Raw Exposure Bias" value shown in Exiftool. Could you explain how to use it?

DNG files contain a BaselineExposure value written by Adobe. I examined several Fuji raw files and their corresponding DNG files. In some raw files I have, LibRaw's FujiExpoMidPointShift is always -2.72 but the DNG's BaselineExposure is 2.15 and 2.51 depending on the ISO. In other raw files, FujiExpoMidPointShift is -0.72 and BaselineExposure is 0.15. Is there a way to convert between FujiExpoMidPointShift and BaselineExposure?


Yes, this is Fuji tag 0x9650

Yes, this is Fuji tag 0x9650

There is no public info how Adobe uses it.

-- Alex Tutubalin @LibRaw LLC

Alex, thanks for your reply.

Alex, thanks for your reply. Is there any info about how to interpret FujiExpoMidPointShift and apply it to an image?

At least with BaselineExposure, Adobe published information on how to convert that into a tone curve.