GammaInfo in Canon DPP4

[rickychan]

The GammaInfo in DPP4 can be r/w by the tag name such as GammaContrast, GammaColorTone, GammaSaturation ...

but how about GammaInfo in other picture style group such as Portrait, Landscape ..., they should be in between TagID 0x20a01 to 0x20a20

[Phil Harvey]

These haven't been decoded.  These are 136-byte records, and it may be difficult to present this data in a useful way.

- Phil

[blue-j]

I don't see them reflected in the DPP4 UI either, and the values appear non-functional to me and unrelated to gamma. Are they only available/written meaningfully with HDR?  - J

[blue-j]

if someone could give me an example, i'd love to have a look.  one things that comes to mind in the realm of gamma correction and 136 bytes is a LUT for 128 points from 0-256.  that is a gamma correction method.  - J

[Phil Harvey]

It appears the data is in the same format as the already decoded GammaInfo record, but apparently for the individual PictureStyle settings.  I could probably add decoding for these if I knew which settings they corresponded to, but it would add significant bloat to the ExifTool output for information that probably nobody would ever care about.

- Phil

[blue-j]

we exhume gamma correction data and show it in a curve or histogram in our software.  we consider it educational and informative.  (gamma correction is too shrouded in mystery IMHO).  then again, we are doing many things no one has ever done before, so probably would not be a common request!  - J