Didn't Minolta make a 110-format SLR, about 20 years ago? Quite a popular executive-style toy, as far as I recall. Possibly this 30mm enlarging lens was made for that. I don't know the size of 110 negatives.(posted 9446 days ago)You can get a first approximation of the coverage of a lens by holding it close to a window, with a sheet of white paper in the position of the film. You'll get a circular image, and the diameter will be a little larger than the film format diagonal. It's larger, because the edge of the circle will have too much fall-off to be usable.