<p>I have a Mamiya 645afd and experiencing unintended multiple exposure issues. I am not turning on the multiple exposure feature. It has happened with more than one film back. The only thing I have noticed is that with one film back it has a blue handle on the dark slide and that one does not do double exposures while the other one with the red handle does have double exposures. Is there a difference between the two film backs? One serial number starts with T (red handle) one starts with B (blue handle).</p>
