I feel like every SLR I own suffers from uneven frame lines, and most of them vary between 1-3mm give or take. I've never had a new film camera, I learned on an AE-1 in the 90s and currently use various Nikon and Olympus bodies these days, so I have no idea if this would have been common when the cameras were new. Is this something that maintenance can improve or is it just the nature of the film winding mechanisms and their manufacturing tolerances?
