Actually I would think that it would be easy to figure out the focal length.
The actual distance from the existing lens to the film plane. Aperture is
a bit more complicated if I recall properly, but I've forgotten a lot more
about optics than I remember.
At 10:17 PM 1/3/2003 +0100, you wrote:
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
Outside of a dog, a book is man's best friend.
Inside of a dog, it's too dark to read. --Groucho Marx
