Quote Originally Posted by Richard Kelham View Post
Mine is also an oldish one converted to AI. Excellent sharp lens, but avoid stopping down to f32 as there is noticeable diffraction setting in that certainly takes the gilt off the gingerbread!

Um, Richard, the smallest aperture that it makes sense to use depends a bit on magnification. At 1:1, the effective f/number is twice the f/number set. Since the most resolution obtainable is ~ 1500/effective, if we set the aperture to f/32 at 1:1 the best we can hope for is not much better than 20 lp/mm.