A RETROSPECTIVE ON BAD CAMERAS
There are many who read these posts who have little or no experience in buying a used camera. I would like to offer perspectives on SLR bodies to largely avoid. There were some troubleprone cameras made and time has allowed us to be better judges of just which ones they are.
I offer the following SLRs, due to frequent jamming: Petri FT II (maybe even ALL Petris, although their lenses are superb). Also, Praktica tends to jam too often. Zenit, as simple as it is, can have bad quality control and for that reason can be one to avoid. Also, Topcon UNI (NOT the RE though, which is good). The Yashica electronic cameras sometimes offer problems.
There certainly are exceptions to all of these but, generally, these are the worst in my opinion. - David Lyga