Hi Fred, > I think "monocular" would be be OK, but I think that what he created > is now to be used as a "loupe"
Actually, a 58/2 Helios lens with all elements but the front one gone is properly called ... lens. Yes, in the optics sense, it is a simple convex lens (made up of one element). And in the photographic sense, it is a lens with some focal length (probably not 55mm), some aperture (probably not f/2), and aperture and focus rings. Cheers, Boz
