clens uses the same lens calibration data as Thomas Niemann's PTLens. Thomas hosts a web site where you can get the most up-to-date lens calibaration data. Please go to:
http://www.epaperpress.com/ptlens/
and get the calibration files from the "Downloads" section.

Once downloaded, uncompress the zip file in a directory. This code looks for version 4.2 profiles. The file "profile.txt" contains a list of all the other profile files. You will need to pass the full path to profile.txt to clens when running the code.
