I once adapted a 135mm f/2 Canon FD lens to an EOS camera keeping infinity focus but losing auto diaphragm operation. It is an impressive lens - got it when my school decided to "dump" all FD equipment. I also acquired this 400mm lens and used it to advantage in Tanzania on the Serengeti. It can be used with a "glassless" adapter but focus is limited to about 15 feet - or with a barlow adapter of 1.25x fl and losing one stop. See it here: http://www.davidhazy.org/andpph/2012-pix/2012-canon-400-telephoto-8535.jpg I also did an adaptation of a 19mm FL lens to EOS which was a cinch. This is a "breech-lock" FD not the rotating lens type. I am thinking that I will do the conversion on this lens as well but would be interested in your comments. Andy
