Vivitar 400MM lens repair neededgreenspun.com : LUSENET : Canon FD : One Thread
This lens is (or is supposed to be...) held together by four very small screws that attach the front assembly to the internal focusing "slide" (sorry I don't know the exact terminology). The screws have all pulled out. It looks as if the ring that holds the front lens in is threaded - I think if I could get that to turn out, I could replace the screws, but I cannot get the ring to turn. Maybe it's "glued" or maybe it takes a special tool...
-- Ken Lotterman (email@example.com), December 27, 2001
If that lens is like most others, the front ring should screw out with the right tool. Try to find a cylindrical object about the same size as the ring and then put a rubber sheet over it to increase friction - I use a latex glove on a glass. A drop or two of isopropanol on the threads loosens up the crud and allows the ring to turn out.
Good luck & cheers,
-- Duane k (firstname.lastname@example.org), December 28, 2001.