Archived posting to the Leica Users Group, 2001/01/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Pascal >>why would these lenses need an aspheric element to deliver top-notch performance??? even the newest Summilux-R 50/1.4 did not need such element.<< I wonder if this is really and apples to apples comparison. Modern aspheric elements are pressed (molded) not ground. (Though amazingly, I believe the asphericaL elements were ground in the original 35/1.4 Aspherical). I also believe in most cases aspherical elements are pressed from plastics, not glass. Somebody please correct me if I'm wrong. There are limits on manufacturing aspheric elements. The bigger the element the more difficult to manufacture. Don't know if there's a theoretical limit on size, but I know there's a practical limit, particulary in terms of cost. Aspheric elements may be practical to use in an M lens, and not in an R counterpart. Dave