I just purchased a used, but in good shape, Pentax 300/4.5 FA lens. However, I think there is a problem with it. When I put it in manual focus, and move the collar to infinity or it's shortest focusing distance.......the collar (not the focusing range) continues to move or slip beyond the limit. I thought the collar should stop at both extremes.....period. Is a screw loose somewhere? Is this easy to fix??
Your help would be appreciated. Robert James
