I found an AE-1 in a local Pawn shop today, and everything looked really nice on it EXCEPT : I opened the back and fired a frame on bulb, and the shutter curtain didn't appear to open. When I advanced the film winder lever, the curtain reset, but I tried again on different shutterspeeds, including holding the button down for several seconds on bulb, and I never saw the shutter open. It freaked me out so bad I didn't even ask the price, just said thanks and left. I'm sure the :shock: showed on my face. It was just wierd. It sounded normal, just couldn't see the curtain moving. Is this normal for the AE-1? Does the camera "know there isn't any film and the back is open, so don't fire the shutter normally? Or, should I stay away?