ok so i've got a 1000f; all is well. but i'm looking to get a polaroid back for it. can someone educated on the subject please give me a rundown on the whole thing? what polaroid backs (if any) will fit the 1000f? what polaroid film type should i use? is polaroid film still available enough that it would be worth it to get a back? where is a good place to buy from? et cetera.... please let me know! i'm looking to make a purchase soon. thanks, b.a.g.