Quote Originally Posted by TheFlyingCamera View Post
I'm holding my VP-1 in my hands right now. Although it may not actually reduce the power by 5 stops, it is marked on the front of the dial from full to 1/32 power (-5 stops). If you are planning to use a Vivitar 283 with either a very modern film camera with advanced electronics or a digital camera, I would highly recommend using it with either a safe sync, or via the PC socket. Don't use it across the hot shoe because they're highly likely to put out way too much juice and fry the TTL circuitry at a minimum.
I'll go so far as to repeat this warning plus warn as well that some cameras may also be damaged if you use the PC socket. It seems that for some cameras that have a PC socket (relatively rare now) the PC socket is designed to handle higher trigger voltages than the hot shoe, while for others the trigger circuitry in the PC socket and in the hot shoe is actually the same, and it is difficult to tell which is which.