Hi guys, I've been lurking here for a while, and unfortunately, I'm introducing myself to get help with my new camera. Today, I picked up a Mamiya M645 with AE prism finder and 80mm lens. I just ran a roll through, and I think I did something wrong, but I've scoured the web and I've read the manual from cover to cover, and still can't figure out what I'm doing wrong. I loaded a roll of film, and it advanced to the first frame without an issue. Here's where things get confusing, and where I'm having trouble finding answers. 1) First, after I shoot a frame, the viewfinder goes black, and stays black. I've read this is normal for some Mamiya models, but couldn't get an answer for mine - is this normal? 2) The exposure counter didn't move from 1, though I eventually made my way through to the end of the roll. I'm going to get my film processed tomorrow morning and maybe that will give me more answers, but could there be something obvious that I'm missing here? Could it be a faulty film insert? I'm pretty sure I loaded the film correctly as I followed both the manual and videos I found online. If anyone can help, it would very much be appreciated.