> Albert Lau has experienced what I assume many have in regards to the C645 (Expensive) Polaroid back. Recently rented a C645 Pol. Back from Samy's camera in L.A. Discovering the same problem, intermittent power off and on, also would sometimes fire in continuous mode with the dark slide in! The rental manager was amazed and tried a brand new polaroid C645 back and it malfunctioned as well. Finally, the store manager pulled a third back from new inventory and voila, it functioned correctly. The moral of the story? Hasselblad has definite advantages in the instant film department. I recently purchase the Contax 645 and am slowly discovering a multitude of design flaws that I will probably be unable to overcome. I also purchased a new 120 film back and insert which would not initially latch positively to the C645 body. After repeated attempts at mounting to another body in a store, the back's spring latch "broke in" and appears to be o.k.. I suppose the plastic has aesthetic and techno appeal, but I am wondering if Contax's manufacturing QA has a ways to go before it can stand up to metal at this time.