[Digikam-users] Image artefacts as a result of vignetting correction

Jan Wolter jan.wolter at uni-paderborn.de
Mon Jul 7 10:26:32 BST 2014


I'm using lensfun (I tested the version 2.8 from sourceforge and the 
newest git version 2.9) with digikam (tested with version 4.0 and 4.1) 
under Linux Mint 17, 64 bit, Cinnamon. I shoot photos with my two Micro 
Four Thirds cameras Panasonic GF-3 and Olympus OM-D E-M1 and I use the 
following lenses: Lumix 14mm, F2.5; Olympus 12-40mm, F2.8; Olympus 45mm, 
F1.8 and Olympus 17mm, F1.8.

When I apply the lensfun corrections in my RAW development workflow I 
get crazy image artefacts in the upper three quarters of the image. 
Please compare the screenshots you can find here:
The artefacts comes from the vignetting correction (if the subject 
distance is >0), because when I deactivate vignetting from the list of 
corrections, such artefacts are not present.

The problem occurs with all combinations of cameras and lenses, as long 
as for a particular lens vignetting corrections are defined in the 
corresponding xml-file under /usr/local/share/lensfun.

Does anyone has the same problem? Or can reproduce it with my raw file, 
which you can download here: 

Yesterday, I wrote this message to the lensfun mailing-list, because I 
suspected that its a problem from the lensfun library. But Torsten 
Bronger (I guess he's one the lensfun developers) replies that he can 
not reproduce the error with darktable and assumed that it's a digikam 
problem: http://sourceforge.net/p/lensfun/mailman/message/32569578/

Can please someone test the vignetting correction with my raw file and 
give me feedback?

Best regards,

  Jan Wolter, M.Sc.        | e-mail: jan.wolter at uni-paderborn.de
  Universitaet Paderborn   | http://ag-kastens.cs.upb.de/jwolter
  Fakultaet EIM/Informatik | Office: F2.303
  Fuerstenallee 11         | Phone:  +49 5251 606683
  33102 Paderborn, Germany | Fax:    +49 5251 606697

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