Thank you @phweyland and @Thomas_Do . What you describe is what I expected, too. But selecting one tag requires a formular. And if there is no variable in the formular, you will get values that are not correct or the value keeps empty.
One example is “Exif.Photo.Aperture” or “Exif.Photo.FNumber”. I can’t find the corresponding variable.
So how do I get the aperture or f-number to the image I want to export? Because of
is a corresponding variable I tried
which I found in the preferences for the GUI. But that variables don’t work
Aperture an FNumber are only examples. Theres are other variables missing
I did some testing with an older image. Aperture f/2.8, ISO 100, focal length 24mm, exposure 1/1600. I set some values with variables and checked with exiftool after exporting. The result:
$(EXIF_APERTURE) → exiftool is reporting a value of 1.0, should be 2.8 $(EXIF_ISO) → exiftool is reporting a value of 100 = correct $(EXIF_EXPOSURE) → exiftool is reporting a value of 1, should be 1/1600 $(EXIF_FOCAL_LENGTH) → exiftool is reporting a value of 24 mm = correct
Is this a bug or is my understanding of the export options wrong?
Then the current list of tags (snapshot above) is currently limited.
I’m trying to get them directly from exiv2. This would provide a complete list of tags which can be used with an image.
NB. exif tags come straight away from raw image (except maybe geo tags for example). So you don’t need to set them. Here the utility would be to remove them from the exported file (no formula), if you don’t want them.
The variable expansion does what it is intended to do. However this expansion is sometimes not compatible with the format of the exiv2 tag, in particular when its type is Rational or SRational.
I don’t see any simple solution for that. One possibility would be to create a specific variable for each problematic exiv2 tag. I’m not convinced this is desirable (case by case stuff, maintenance issue, …).
But I think your initial need may be satisfied. In fact you wanted to remove exif tags except some of them. For that we don’t need the variable expansion.
I’ll try to find a way to do it.
I suggest this the following. If you have disabled exif tags but you want to see some of them you enter the sign “=” in the formula.
@phweyland Thank you, your suggestion sounds great. Is it possible to remove the serial number of the camera and the lens with this new solution or is the serial number one of the problematic exiv2 tag?
How can I play with this new solution, is it already in the the actual git version?
Thank you very much. Now I had the opportunity to try the export of the Exif data. This is perfect. Thanks again and I hope that your change will be implemented and published in the official code quickly.
when I edit aperture=8 in my manual lens in lens correction this value is not stored if I export the jpg with export module.
also “Exif.Photo.ApertureValue =” in preferences of exportmodule does not help.
how can I change the aperture, focal length, lensmanufaturer manually in darktable 3.8.1?
i a have a manual lens.
I just want the edited photometric parameters from lens correction module in exif data of my jpg.
Exif.Photo.FNumber=8 is working, but then I have change for every foto this metadata.
Is it possible to set a variable that reads out the information of aperture of the lens correction module?
my goal would be to readout the 3 infos of the lenscorrection module