How to use Lensfun?

Lensfun itself is only a library for correcting several artefacts and a database for storing lens profiles. To actually use Lensfun to process your images you need an image editing application with Lensfun support.

So far you can use Lensfun with the following applications:

ACDSee commercial image viewer and editor (since version 9)
Affinity Photo commercial image editor (since version 1.5)
Darktable RAW processor and photo workflow software similar to Adobe Lightroom
Digikam/Kipi image management application, supports Lensfun via Kipi-Plugin
Exposure X3 commercial non-destructive RAW editor
GimpLensfun GIMP plugin
Hugin panorama stitcher (version 2011.4.0 - 2014.0.0)
lensfunpy Python wrapper for Lensfun
ON1 Photo RAW commercial RAW processor and photo editor
Photivo photo processor application
Rawstudio another raw processor
Rawtherapee raw converter and image processor (since version 5.3)
UFRaw is a standalone raw processor but also contains a GIMP plugin to load RAW image files

If the above applications do not recognize your camera or lens in their Lensfun tool please check the list of supported lenses and the FAQ.