Originally posted by p0opstlnksal0t you say yours works fine as a stop down lens... why is this? did the mount modify it in a way that it no longer functions properly wide open? also what did you remove from your 28mm? ive never taken a lens apart, is it even possible to "remove" bits to get the same depth as with the original MD mount? also, are you talking about just using an m42 back plate from like a trash lens then swapping it on?
on the kiron lens (and also a vivitar 24mm for nikonbuilt by kiron) the aperture activation lever is an integral part of the old mount, including bearings to keep it moving freely.
when you take off the old mount all of this comes off in one peice. I cvan't say what will happen on a minolta lens, as I have never happened across one of those yet.
When I took the bottom 5 screws securing the mount, I also removed a 0.8 mm shim (the mount was 1.8 mm thick). I don't know what you will find on you r lens
I then had to remove part of the back of the aperture setting ring, as it had a flange on it that would get in the way.
this was ground off with a large wet grinder I have.
with all this done, drilling the flanged mount to the correct hole pattern then countersinking the screws allowed the new mount to be installed.
Note : I got the F2 28mm for $5 because it had stuck aperture blades (a common problem with kiron lenses of the early 1980's), so I was not sacrificing a lot in terms of money for the attempt.