I'm not even sure how I found this, I wasn't looking for the lens or for Pentax for that matter, but it's a home project this guy is doing to make a circular fisheye on 2 1/4 x 2 1/4 film. The lens makes it on topic. Just thought I'd share.
http://www.angelfire.com/ca/erker/fisheye66.html This is a man after my own heart, tinkering but keeping the original equipment intact. -- Remember, it’s pillage then burn. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.

