camera/lens not found

Software darktable
1

I have already brought up this topic on Reddit, but did not get anywhere there.

I’m pretty sure I’ve already used this camera/lens combination successfully. But that was with Darktable 4.8.x. In the meantime, Darktable has been updated to 5.2.1 and I’ve also switched from Manjaro to Arch. Now I have new photos taken with the EOS R7 and Sigma 16mm f.14 combination. When I apply the lens correction module, I get the message “camera/lens not found.”

If I understand correctly, Darktable uses lensfun for lens correction. When I look at Lensfun, the Sigma 16mm f/1.4 DC DN Contemporary lens is listed as supported. I have already updated the lensfun database with lensfun-update-data. This has not solved the issue. As a next step, i have found the lens in mil-sigma.xml. The RF mount was not listed here, so i have added manually Canon RF for the lens. But again without solving the issue.

If i choose generic Canon APS-C camera with 1.6 crop, I can choose the lens, but not when i use the EOS R7 as camera.

Can someone please tell me what I can do now or why this combination is no longer supported?

2

4B9A0919.CR3 (8,8 MB)

3

Update your lensfun database.

1 Like
4

I have already done this. It doesn’t solve the issue.

5

You should request that the maintainer add Canon RF to lensfun/data/db/mil-sigma.xml at af05cd72b88648ebe8d3a767f8aeb3f4926422f7 · lensfun/lensfun · GitHub

In the meantime, you can add it yourself.

1 Like
6

Adding only the mount, seems not to be enough (but i’m new to this all). Could it be, that also the cropfactor has to be adjusted? According to mil-canon.xml the EOS R7 has <cropfactor>1.613</cropfactor> instead of <cropfactor>1.534</cropfactor> which is noted by the lens…

7

if the crop factor is off, then you probably won’t get a good quality correction anyway. I’d probably make my own profile at that point.

1 Like
8

I am on DT 5.3 +430 Windows and the sigma 16mm lens is not in the database. Hopefully it will be added soon.

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9

I have added a issue in lensfun GitHub. This is the same edit as i have made manually. But in my case, it did not solve the issue for me. But maybe im to stupid for this.

I don’t know if it is possible on Windows to manually update the lensfun database, but i assume, you can do that.

With DT 5.2.1 you can choose “Generic Camera with Crop 1.6 (Canon)” and after that the Sigma 16mm f/1.4 is selectable as a workaround.

10

I will take a look tonight.

Two things to check.

  1. Your local Lensfun database needs to be version 1 and not version 2.
  2. You may have multiple Lensfun directories. Use the search feature in your OS to find all places.
2 Likes
11

I have not found other directories, but maybe i have made something wrong with the xml file. In the meantime the my issue on GitHub was fixed and i could update the database. After that, the Sigma 16mm lens is available for the EOS R7.

2 Likes
12

How does one submit a lens to lensfun , I noticed pretty much all but 2 of the Irix Lenses are not supported despite having profiles on their site.

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See this PIXLS.US - Create lens calibration data for lensfun