Graywolf wrote:
The opposite. High (or Extra, or Extreme) dispersion glass requires less curvature to obtain the same dioter. In a prism the colors would be spread farther.
Indeed. If it was Extra low dispersion, then the initials would be ELD. Manufacturers wouldn't miss the opportunity to stick _another_ letter into a lens designation - except, maybe, Pentax.
Bending the light more allows one to build smaller optics. It also, as noted, creates other problems....
graywolf http://www.graywolfphoto.com "Idiot Proof" <==> "Expert Proof" -----------------------------------
David Savage wrote:
Extra-low Dispersion I think.
Dave S
On Apr 5, 2005 9:11 PM, frank theriault <[EMAIL PROTECTED]> wrote:
<snip>
ED stands for what?
-frank
-- "Sharpness is a bourgeois concept." -Henri Cartier-Bresson
