Darktable 3.8 Lens choices

I just downloaded 3.8. I find that while my Canon EOS R6 is recognised when I choose it I am offered only RF Lens choices. I am still using the old EOS lenses with the adapter. How can I find them?

Which lenses and what does your slr-canon.xml file contain?

What if you replace mil-canon.xml with https://kameratrollet.se/wp-content/uploads/2021/12/mil-canon-2021-12-16.zip and slr-canon.xml with https://kameratrollet.se/wp-content/uploads/2021/12/slr-canon-2021-12-19.zip

Backup your old files before replacing them.

There is a lensfun-add-adapter command that should help, but I have never used it, so I can’t explain the details :pensive:

Peter, thank you for your reply to my query. I have looked at the available lens in the substitution you have suggested for the slr-canon.xml.
My camera is the full-frame Canon EOS R6 which I assume has a crop factor of ‘1’.
The lens I am using is the Canon EF 28mm f/2.8 USM, This is not included in the .xml file

These are the entries for the EF 28mm lenses:

Canon EF 28mm f/1.8
Canon EF


Canon Canon EF 28mm f/1.8 USM Canon EF 1 Canon Canon EF 28mm f/2.8 Canon EF 1.611

The EF 28mm f/2.8 USM with a crop factor of 1 is not included.

Do you have any suggestions of how I should remedy this?

Warm regards.

My apologies, I must have either exceeded the word count or else putting in the xml code was not acceptable. The bottom line is that the EF 28mm f/2.8 USM with a crop factor of 1 is not included

Thanks @pitbuster Felipe for your reply. I am not technically knowledgeable so I have no idea how to use the lensfun-add-adapter. If Peter can’t suggest a solution I will work on trying to understand the adapter.

The xml code is filtered out because it’s too similar to HTML code, which could be abused.

You can however format it as preformatted text by selecting it and clicking the </> button or making sure each line starts with 4 spaces.

Indeed the EF 28mm f/2.8 USM hasn’t been added to the database:

But as you have the lens and a full frame camera, why don’t you take a series of photographs that are suitable to generate the calibration data and submit the raw files?


I see. Then you will have to create it yourself. It is a prime lens so it will not be too hard for you. I have published some YouTube tutorials here When will Sony A7 IV profile be added to Darktable? - #6 by Peter

I’d suggest just looking at PIXLS.US - Create lens calibration data for lensfun as the other articles are really old and might just serve as a historic reference

Yes the lens calibration tutorial on Pixls.us is the first one that is linked on the lensfun website.

And from what I see, the lens still needs to be calibrated for full-frame cameras, as the only similar lens (EF 28mm f/2.8) has only been calibrated with an APSC body.

So even if the optics between the non-USM and USM are sufficiently similar, it won’t help you when you want to correct photos taken with a full-frame camera.

The good thing is, that one only needs to submit a set of suitable raw images and the lensfun devs/volunteers will do the calibration.
But the calibration process is also nicely explained in the tutorial.

I’d do it yourself if possible, the queue is long!


+1 and you’ll learn a lot and have the calibration data available even if it’s not yet merged into lensfun

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