(1) I have a Canon F1n w/AE Finder that has been to Canon twice for cleaning, calibration and parts replacement. It has served me quite well until recently, when remounting the AE Finder I noticed that the right-hand-side (manual) exposure scale in the viewfinder is blocked. (I can only see a tiny fraction of the shutter speed indicator at the bottom) The lower (Av) scale works normally when I set the shutter speed dial to 'A'. It appears as though the 'blind' that covers the right-hand-side scale when the shutter speed dial is moved off A is stuck. I suspect (rather, 'hope') that the problem is common or trivial and that the remedy is equally trivial. Has anyone had a similar problem? (2) As a side note, I've been using a Canon FL 58mm f/1.2 for some time before I noticed in the manual that I'm not supposed to be able to mount this lens on the F1n. Could this be the source of my viewfinder problem above? If not, can anyone tell me why I'm not supposed to be able to mount this lens, since it seems to work fine otherwise? (I've only ever shot negative film with it, so I can't vouch for its exposure accuracy.) Thank you in advance for your help and insight.