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I'd like to use the Lens Correction module in Darktable. My photos are taken with Samsung S8, and Darktable does not have the information about the lens in this phone.

How can I add this information? Thanks!

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    Assuming you're working with RAW files (which is what lensfun is designed to work with) you might want to also submit a sample of one to raw.pixls.us to help with getting full RAW file support into darktable. – junkyardsparkle Jun 2 '18 at 17:18
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RawTherapee, darktable, and other programs use lensfun for lens correction. If your lens appears to be absent from the database...

  1. Check the Lensfun coverage database to make sure it really hasn't been added yet. If it's already there, you may need to update your local copy (sudo lensfun-update-data).

  2. If your lens is not supported, you can read about how to calibrate it:

  3. If you can't (or don't want to) figure out how to calibrate your lens (it's not easy, and this is the approach I've taken in the past), you can send calibration images to Torsten Bronger. He will send the calibration data to both you and the lensfun maintainers.

junkyardsparkle notes:

... Make sure that what you want to correct is actually correctable with a lens profile. There seems to be some confusion about this amongst people submitting phone images in particular. The RAW files from my S6, for example, are already quite rectilinear.

Also, calibration images must be in RAW formats for RAW-capable cameras because many modern cameras (eg, Fuji) automatically correct lens imperfections when generating JPEGs.

  1. If you can't (or don't want to) take calibration images or wait for a large upload to complete, some programs allow lens correction parameters to be entered manually. You may be able to find, by trial and error, parameters that you like.
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    First, though, make sure that what you want to correct is actually correctable with a lens profile. There seems to be some confusion about this amongst people submitting phone images in particular. The RAW files from my S6, for example, are already quite rectilinear. – junkyardsparkle Jun 2 '18 at 17:25
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    "RAW" as in the DNG files. The lensfun profiles are for RAW files from cameras, at least for any camera that can produce such files. This is significant, since many modern cameras produce JPEGs that have already had corrections applied. In the case of phones, this can be slightly complicated by the fact that some models only produced JPEGs initially, but gained the ability to save RAW formats later because of updated firmware. – junkyardsparkle Jun 3 '18 at 4:07

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