You can find 6x6 backs (as well as 6x4.5) but they're not as common as the 6x7 backs. Tried a Mamiya 7, and though I liked it, I just can't get into rangefinder

You can find 6x6 backs (as well as 6x4.5) but they're not as common as the 6x7 backs. Tried a Mamiya 7, and though I liked it, I just can't get into rangefinders. The framing not being exactly what the image will be always bugs me.