This week I'm shooting with a Bronica ETR and a 50mm f2.8 Zenzanon MC to test out a 35mm panoramic back (Bronica 135 W) I won on eBay. I've put 2 rolls through it so far with one more test roll tomorrow. First, before I even took a shot, the leather that covers the screw that holds on the manual film advance lever fell off as did the screw. I screwed it back on and it seems okay. Then, the pin you push in that allows you to rewind the film fell off and is lost. I've been using a paperclip in lieu of the original pin. With the first two rolls I'm getting several double exposed frames. But the spacing between frames is near perfect and the few good images are nice and sharp. The 3rd roll I shoot tomorrow will be with a different ETR body and then I'll know where the problem lies. The eBay seller claims to never have had a problem with this film back..... of course.