I do not understand. If you are going to adapt old teles there is probably nothing at the back of the barrel but the mount. Why not cut off the mount shorten the barrel however much is needed and graft on the new mount. Only problem I see is that it would probably be a beach to get the auto diaphragm to work.
Aside to Tom S, I'm jealous. I do have an 1892 watchmaker's lathe but the spindle is bent, so it is on display in my living room. Oh well, I seem to be in an audio/electronics mode right now anyway. -graywolf Cory Papenfuss wrote: >> Pentax K register distance is 45.46mm >> Canon FD register distance is 42mm >> >> This means that to alter an FD lens to fit a K mount camera (without >> using an adapter containing an optical element to correct for infinity >> focus) you would have to remove over 3 and a half mil from the back of >> the FD lens flange. If you're going to use a 42mm threaded adapter, then >> add the thickness of the adapter to that. Might be problems in that >> there's not enough room on the back of the FD lens before problems start >> in terms of aperture ring etc. You may or may not have problems with the >> rear element of the lens not clearing the mirror. I don't have an FD to >> look at, but where there's a will, there's a way. >> >> I have some links on the bottom of this page that might be of further >> interest: >> >> <http://www.cottysnaps.com/snaps/mods/details.html> >> >> It's a big job but as an engineering exercise, viable, if expensive. Of >> course, as a hobbyist, cost is not justifiable so go to it! >> > Registration distance will definately be a problem for this > exercise if you want to try to maintain infinity focus. Last time I > handled an FD lens, the breech-lock seemed "smaller" in diameter to the > K-mount flange... Maybe it could be made to fit *inside* the K-mount body > by 3mm? Of course mirror clearance is a big problem, but maybe for the > smaller mirrors of the APS-DSLRs it's OK? > > -Cory > > -- > > ************************************************************************* > * Cory Papenfuss, Ph.D., PPSEL-IA * > * Electrical Engineering * > * Virginia Polytechnic Institute and State University * > ************************************************************************* > > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
