It's hard to tell in a picture. Lenses get swapped around a lot on these, although it was common to have a slightly longer than normal lens mounted, I have a 4x5 that came with a "5x7" tessar on it, but that lens was a good bit older than the body. If you are familiar with both size cameras you can tell just by picking it up but the best way to tell is to measure the back or a holder. 3x4 is a nice size for hand holding, very easy to manage.