Canon CR3: Sigma EF-M 30 mm F1.4 lens not correctly identified

Issue #195 resolved
Danny Heijl created an issue

When browsing CR3 files from my M50 the lens type is shown as Sigma 56 MM F1.4 DC DN while in reality it is a Sigma 30 MM F1.4 DC DN.

When editing the file, the lens correction profile is also not found by the automatic detection, although it is present in the lens database and I can select it manually (the 56 MM F1.4 DC DN Sigma is not yet in the Lensfun database). The exif info correctly shows the 30 MM focal length.

Canon DPP 4 correctly identifies the lens as a Sigma 30 MM F1.4 and also correctly applies the lens correction (that seems to be embedded somewhere in the CR3 file).

I attach a CR3 file that shows the problem.

I tested both with the official 1.9.3 Windows build, and with the latest nightly build.

Comments (4)

  1. Gaaned92

    exiftool also reports this lens as a “lens type”: “Sigma 56 MM F1.4 DC DN” while identifying the focal length as 30mm!!

    The lens type is numerical and equal to 4208. It is decoded by exiv2 or exiftool to provide a name. This name is the used to find the corrections in the lensfun database.

    So there is an error in the decoding by exiv2 or exiftool.

    As ART uses exiv2 to identify lenses, I think the best should be to report this issue at https://github.com/Exiv2/exiv2/issues

  2. Danny Heijl reporter

    I followed the advice given in the exiv2 issue #1782 and now it works:

    This is because this lens isn't known to exiv2 yet.
    As a workaround, you can use a configuration file as explained here

    Just add the below to said file

    [canon]
    4208=Sigma 30mm f/1.4 DC DN | C
    

    and exiv2 will report the correct lens name:

    Exif.CanonCs.LensType                        Short       1  Sigma 30mm f/1.4 DC DN | C
    

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