So I just ran a couple of rolls through my new-to-me Kiev 6C. The first roll was fine, but the second roll had two shots that only exposed the right edge of the negative. Most of the shots were taken at f11/60 except the two bad ones, which were taken at f4/500. Obviously the issue only occurred at the higher shutter speed. It was also very cold outside if that matters. I don't have a scanner to show what it looks like, but it looks like a flash sync issue but without the flash. Does anyone know what could be causing this? I know that Kievs have a reputation, but I'm trying to get a handle on the potential cause and any potential solutions to it. Is 1/500 just hosed? Does the shutter just need some exercise? Am I missing something? Any ideas before I blow through a bunch of film on this would be appreciated. Thanks!