I've never shot instant film and I don't know how it works. However I can get at least ten boxes of FP100C color instant film for $15/box. I think this is pretty cheap--is it? That's not much more expensive than good B&W film, and I could use the film for proofing, I suppose. I understand that I need a special back to shoot it, though. I have a Speed Graphic with a Graflok back. Do I need a special Fuji back, or some kind of polaroid back? There are many different kinds of Polaroid back I have found.