Dear List, I just picked up a nice used RB67 and 37mm fisheye. I want to shoot the full 72mmx72mm frame and that means shooting 4x5 film, giving an almost 3" square image. Apparently both Mamiya and NPC made adapters for the RB67 that mated a Polaroid 545i back to the camera, which would allow me to use ReadyLoads or QuickLoads. I was curious if anyone ever had any experience with such a beast? Thanx in advance.