Originally posted by RonHendriks1966 No it doesn't support 36x36mm with K-mount without dark edges. It supports 36x24mm and adjusting to a square you will get less then 36mm. No idea how much, but it should be just a thing of mathematics.
You're right. The 36x24mm diagonal is 43.26mm. The square-sensor image circle could be no larger. With the closest square sensors:
30mm square, Diag= 42.43mm, Area= 900mm^2
36mmx24mm, Diag = 43.26mm, Area= 864mm^2
31mm square, Diag= 43.84mm, Area= 961mm^2
So a conservative square sensor would be 30mm per side, with area just slightly greater than 36x24mm FF. Thank you, Pythagoras!
But a 36mm square sensor would allow 36x24mm (either way, portrait or landscape) or 30x30mm or various other sizes at different aspects, all within a 43.26mm PK-mount image circle. Selecting the aspect in-camera is enticing. Professional? No. Fun? Yes.