There are a number of photographers out there who consider the 6×7 format of medium format film to be the only really medium format type. Part of this has to do with the fact that it’s right in between small format (35mm) and large format (4×5). It’s quite a bit larger than 645 format and much larger than 35mm format. It can also prove to be very difficult to work with simply because you need to be super critical about your focusing.
So if you’re looking for a 6×7 format camera to work with, check out this list.