How to learn image dimensions in Darktable?

darktable uses Exiv2.

$ exiv2 -pv raw-file.CR3

Compare what the difference is between the cropped one and the non cropped. Change the cropped one with exiv2. I have vacation now for a month and will not be near my computer.

The rawprepare module takes care of cropping the whole sensor data to the size exif data is telling.

There are sliders that can override exif settings, by default they are hidden for safety reasons.

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Please look at the answer of @Peter #19. He found out the best you can do right now.

Peter, I’ve been using ExifTool for some time now. I have been able to change the aspect ratio elements in the metadata (Makernotes) successfully (Note: the image file I previously uploaded after changing metadata was NOT completely changed. It’s still flawed). That appears to provide a way to fix the raw file. In that, before investing time and effort to develop. However, it does NOT appear to be any help when it comes to salvaging past work done on developing an image file.

Even though I did nothing to alter the aspect ratio (or size) of the image it looks like something is present in the sidecar file that preserves the aspect ratio in effect when the developing was done.

There is NO mention, that I can find, of “rawprepare” in the User Manual which by the way I’d say is quite thorough. However, I do notice something called “rawprepare” that appears in sidecar file. Looks like it is first in line. However, it’s NOT at all clear how the parameters are encoded. It looks to me like knowing how to make such a change might be the way to deal with this problem.

Is there documentation on “rawprepare” that I could review?

It’s the raw black/white point module, that also does the crop. There is a config option, disabled by default and I can’t remember the name unfortunately right now…

grafik

grafik

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Very good! That looks like it does the trick.

I might point out that before knowing how to “allow_editing_cropping” I fiddled with the “raw black/white point” module such that it appears based on history stack to have rerun. It looked like now that the raw file has the aspect ratio metadata changed to the desired value that the edited version was changed accordingly. In that, I didn’t have to do anything with sliders. It looks like using those requires knowledge of how the camera crops the sensor data when producing the raw file.

I sort of like being able to see the crop settings even if I don’t want to change them.

Many thanks, looks like this solves my immediate problem.

With that said I would suggest that when it comes to post-processing raw files the user should have the option to use all of the raw data. If the software wants use camera settings for creating a default option that’s fine but the user ought to be able to change that as a normal course of action. In that, it should NOT be necessary to revise metadata in the raw file to get this done.

Thanks again for the help.

Yes, this sounds like a mismatch between how libraw and rawspeed handle the raw data. You can open a report on github to have someone look at it.

Would that be what is referred to as an issue on this site?

Yes.

Nice found.

Thanks to hannoschwalm. I didn’t know about that.