Here are a selection of papers on all-sky lens calibration:
A new positional astrometric method for all-sky cameras.
This link will take you to the SAO/NASA ADS Astronomy Abstract Service where you can download the pdf. Below the abstract select Printing Options and then Print Whole Paper. Next press the send pdf button. A download of the pdf will follow.
Segon, Darmir, (2009) How many stars are needed for a good camera calibration? WGN 37:3, pp. 80-83.
Houghton, John (2008) Lens Calibration Using the Stars. Web page.