I just bought a Hasselblad 501CM with an 80mm CB lens. I've noticed that when I hit the shutter release button the shutter closes quickly, then opens for the normal exposure time, and closes again. I never paid attention to my 80mm CF when I tripped the shutter, but this just doesn't seem right. Am I wrong, and is this normal? I bought the camera from someone who hardly used it (and was the original ownder) so I'm thinking (and hoping!) that this might be normal. Thanks in advance.