confused: Sigma lens not recognised by darktable (Linux Mint Xia)

Software darktable
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1

TL;DR:
OK - I was already able to solve this using a .exiv2 configuration file, but I’m really a little confused and perhaps someone has an idea, or may point me to some resources, since I’m new to the platform I’m currently using…

The long story…
As I’m quite used to compiling darktable under Windows 11 MSYS, I had no fear of starting to play this game also on a fresh installation of Linux Mint Xia the other day :sunglasses: Everything worked out fine and darktable was up an running. So far so good :blush:

Recently I did some shots with my favorite Sigma 24mm f/1.4 DG HSM Art and found, that the lens was not recognized by the lens correction module. I first sorted out lensfun, as the lens was even not available in the lens correction module (seems, as if I had an old installation on the system → changed this to a fresh self-compiled installation). So I was able to select this lens.

But the lens was still reported with its Lens ID 126 in the EXIF data instead of the string I knew from my Windows installation. So I checked my exiv2 installation. Well, OK outdated too, so I repeated my steps for exiv2 - did a fresh self-compile which unfortunately didn’t solve my problem: when using exiv2 to read the meta data of a NEF file, it still reports Lens ID 126 instead of the string I expected.

As soon as I created a ~/.exiv2 file with the following content

[nikon]
126=Sigma 24mm F1.4 DG HSM | A

darktable reports the string (to be expected now) in the EXIF data and the lens correction module now automatically assigns the correct lens.

Bottom line: everything works → but why the heck doesn’t this also work without using the custom definition file?

Any help highly appreciated & thanks to all of you in advance :wave::blush:

2

Where are you putting the .exiv2 file exactly?

3

I think in the past many aftermarket lens makers didn’t always respect the LensID tag of existing (older lenses) such that the combination between your camera make and model would not be recognized. Your .exiv2 file overrides any other configs wich are standard to exiv2’s normal installation.

I remember having had a Tamron lens which misidentified as an older Pentax way back when. Solved it the same way.

4

I just put it to ~/.exiv2 (just added it to my original post)

5

thanks for your quick reply. Yes, overriding the internal definitions will always work :blush:

Some time ago, I provided the lens correction data for this lens to the lensfun maintainers (as it was just included for a full frame and not for APS-C at that point in time). And there was also an exiv2 issue related to the lens ID which has been solved.
Thanks to the wonderful maintainers these changes had arrived very quickly in the available libraries and builds, so this worked like a charm in darktable on Windows then.

So I’m quite puzzled that I experience such problems under Linux now… :thinking:

6

Linux Mint is based on Ubuntu LTS, so sometimes the software is quite out of date.

7

You are absolutely right Mica, was my first assumption and therefore I uninstalled lensfun and exiv2 and did a self-compiled install for both so still → :crazy_face:

8

Yeah the problem with that is, when you install something else that needs one of those libraries, the package manager will pull it down again.

9

Good to know… Thanks for pointing this out :+1: