There is a book, "Photographic Cameras and Accessories" published by Lindsay Publications (http://www.lindsaybks.com/), that has information on this. -- Michael Lindner http://www.starastronomy.org *** http://home.att.net/~mikel http://www.atmsite.org *** http://www.atmlist.net _______________________________________________ ATM mailing list http://www.atmlist.net/