I've just got me a Bronica ETRS. I've got my first film loaded up in it. But when I take a picture the mirror goes up (obviously) but then doesn't return to position until I wind the film on and re-cock the shutter. i.e. I can't see anything through the viewfinder. Is that normal? I'm a bit puzzled because the mirror was down before I took the first shot on the film and there's nothing to suggest this in the manual. Thanks.