first of all my specs: I'm using Ubuntu 16.04, my lens is a Tamron 18-270mm F/3,5-6,3 Di II VC PZD and I'm using Darktable 2.0.6. I updated my lensfun library using the article of Torsten Bronger.

My problem: in the lenscorrection module the name of my lens is shown correctly, but all other options are 'greyed' out (see picture below) although the tamron lens is listed correctly in the lensfun .xml file (slr-tamron.xml) under /usr/share/lensfun.

How can I get it to work again? Am I missing something?

Thats what it looks like

  • Which version of Lensfun do you use? – Torsten Bronger Oct 5 '16 at 16:47
  • I updated lensfun using your answer you gave someone previously: "For lensfun <= 0.2.8, you may download wilson.bronger.org/db/version_0.tar.bz2, and extract its contents over your old database, which usually resides in /usr/share/lensfun (clean this directory first)." That was on oktober 5th. – user57234 Oct 10 '16 at 8:20
  • So, you use 0.2.8? – Torsten Bronger Oct 10 '16 at 9:00
  • I guess. The weird thing is that the tamron lens is listed correctly in the .xml file but doesn't show in the dropdown menu in darktable. When I updated lensfun with your tar file new lenses showed up, just this one didn't. – user57234 Oct 11 '16 at 10:40

Lensfun does not offer calibrations for a particular lens model that were done with a too small sensor. In your case, the calibration was made with a Canon, and you use a Nikon. Canon's APS-C is smaller than Nikon's. Because this difference is small and there are so many third-party lenses, Lensfun is less picky in newer versions about that.

Solutions: Update your Lensfun, or set the crop factor in the XML file manually to 1.5 for both the lens and your camera.