Here's a test, do you know your Polaroid backs, or is it just cameras?
There are backs for 4x5" LF cameras, some take 4x5 film sheets, and some take 8x10cm sheets or packs. AFAIK there's no more 4x5" or 8x10cm sheets (except on fleabay), it's all 8x10cm packs of FP100 and FP3000B. Which backs for 4x5" cameras can take currently-produced film packs, besides the Fuji PA145?
And similarly, what's available for MF (specifically Mamiya 645AF and Hasselblad V mount)? All I see are what look like single-sheet holders, or do they take packs? And which of any of these take film that is currently available?