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645 Mask


New Member
I'm a new user, so please forgive if this seems particularly obtuse. I just bought a A16 645 back. It did not come with a mask for the focussing screen. The focussing screen seems to be pretty much 1:1 magnification, so it seems to me that the simple thing to do would be to cut one for myself out of excess exposed film - taking a 6 x 4.5 hole out of the middle of a frame. Any better ideas?


I cut a piece of acetate (clear mylar would do)
to fit over the focusing screen and used a fine tip spirit marker (waterproof felt tip marker)
to draw two lines across the sheet in the correct
spot approxiamately 4.5cm apart centred in the
screen. Worked well and meant I could alternate
between a 6 x 6 back without any hassle. Cheers
The top and bottom markers on the various masks/screens marking the 6x4.5 cm format are 37.5 mm apart, not 45 mm.
Thanks - this is a very helpful list. Now I find to my slight dismay that my new A16 will let me fire the shutter with the darkslide in. My A12 will not allow this. Is my A16 broken, or is a "design feature"?



The slide should indeed "block" exposure. Perhaps your darkslide is bent, allowing the lever inside the back to slide past the darkslide (try inserting it reversed) or the lever itself is in need of a repair (maybe someone tried to change light trap seals and let the mechanism, or part of it (spring) drop out.).