I have a chance to get a Polaroid back that fits my Mamyia 645. Would this be a good thing to have to preview effect of settings for portraits? I would like to see what a shot will look like before the final shot. This is more or less for pics of kids and grandkids.
I presume you're talking about a film back that uses pack film. There is a company in Europe selling hand-made pack film. It is expensive. About 10 euros ($12 US) per shot. ONE INSTANT Packfilm ยง Type 100 P7 Color