Got this in today's batch of stuff; it seems to cover 2X3, but I do not know about quality at the edges of that coverage. 3 1/2" seems a bit short for the format; is it intended for 6X6 or 6X7?

3.5(inches, focal length)*25.4(mm per inch)=88.9mm focal length and an f6.8 could cover 4x5 like a lot of 90mm's.