Just a word of the old Vivitar 283 flash gun. When you find one that works it's a perfect tool. There's more than one but, though. 283 is a very old model and most of them haven't been used for ages. Usually such a flash works nicely a few times but then die a sudden death. Some of the older ones will have a trigger voltage up to 300V, enough to fry any camera with a chip inside, many mf SLRs included. You can't tell the trigger voltage unless you meter it. The 283 needs an additional module for manual power adjustment which is more than difficult to find these days. Finally, 283 doesn't use a normal PC connection for sync cable thus you need to find a special kind of sync cord. On the other hand the new model Vivitar 285HV can be bought as new for $75. It's a better and more reliable flash gun and it's totally useable with any kind of camera.