I have a smallish brass lens, about 1 1/4 inch in diameter, has a rotating disk for f-stops. Reads on the side: "The Scientific Lens Co. Extm W.A. Anastigmat S24
It has an aperture scale from 16 to 256 which I know is really f16 to f64.
What will it cover?
Any ideas as to it's value?
tim in san jose