Lensfun is an opensource database of photographic lenses and their characteristics. it contains three kinds of objects:
* mounts
* cameras
* lenses
it is used in various photo-related software in which it allows the correction of various artifacts:
* distortion
* transveral (also known as lateral) chromatic aberrations
* vignetting
* colour contribution of the lens (correcting said "yellowish" or "blueish"
images)
it provides a way to read and search for specific things in the database.

this package contains the documentation.