Hey I have same setup here and was similarly heartbroken so I played around and figured it out! Depends if your model is like mine. Turned out it was the aperature pin on the lens that was catching the aperature indexing lever on the camera, not the rear element itself. I found that when the lens was switched to manual mode the pin would just flop up into the camera when held rear element up. So I left it like that and mounted the lens with the camera face-down so gravity could hold the pin in. Voila it mounted all the way! I switched the lens back to auto and it works like normal, open aperature (edit: I mean stop-down) metering and all! (Well, with limitations on my buggy spotmatic - see my other thread
). So I think it's just the extra-long pin and probably only happens on the F cause of that lever. Again my model is the electric mc flektogon czj so dunno if it works the same for all. Oh and if I didn't explain it well let me know and I'll post pics.
. Oh and even with deeper rear element, once mounted no probs with infinity. Oh and be warned that removing the land is a little tricky to, just found that out. In order to remove the lens it has to return to manual mode so that the pin can fall forward again so it will clear the aperature indexing lever again. In order to switch it to manual mode, it needs to be partially dismounted , Maybe 1/8 of a turn so that the tiny pin that locks it in auto mode can be un-pressed. Then you have to tip the camera face down and jiggle it so the pin will fall into the lens. Then it can be unscrewed all the way. So, before putting the lens on, I recommend making sure The pin is floppy enough to be reliably moved in and out with gravity and jiggling alone. Otherwise, I suppose this could just be a very nice fixed – lens camera :-)
Oh yah I guess alternatively if you're only gonn a use it on this camera you could just file down the pin.
Last edited by thenewreligion; 09-23-2017 at 05:55 PM.
Reason: Addendum