MagicLantern + manual lenses = ❤

2022-01-17: After being silent for a while, time has come for me to dive into ML and lua scripting a bit. There is a new version of the script in lua.zip. I've moved the lenses definitions to a separate file - ML/scripts/lib/lenses.lua and did some changes in logging. You can also use the lensfun-based generator for lenses.lua at the Supported lenses page.
2020-04-16: I just found out, that when the Exif.CanonCs.LensType is set to 65536 (which is interpreted as n/a aka Not Available), DarkTable does not even attempt to guess the lens from other exif parameters and does not offer automatic lens correction.
So this tag is now completely removed and the autodetection works fine (for those few lenses, which have the necessary profiles in lensfun database).
2019-08-20: Added new lens parameter called note, which is used in the list of available lenses, when you need to differentiate between various pieces of the same type. When present, it is appended to the lens name - see the (#1) and (#2) in the first screenshot below.
{ make = "Helios", name = "44-2 58mm f/2", focal_length = 58, manual_aperture = 2, serialN = "7765411", aperture_max = 2, aperture_min = 16, f_values = {"2","2.8","4","5.6","8","11","16"}, note = "#1"}
2019-08-05: Fixed couple bugs related to autoloading the lens configuration and setting the previously saved output format. Check the updated lua.zip.

Lens list

Lens detail

Script settings

Outfile format