On 28 Jan 2001, at 8:38, Shel Belinkoff wrote:
> It's pretty well acknowledged that Leica used aspherical glass
> elements in some of their early ASPH lenses. They were ground
> glass, and as you said, quite expensive to make. IOW, the
> technology was there early on to make such elements, or
> surfaces, depending on the design of the lens. In fact, Leica
> used two aspherical elements in (help me out here Rob) their
> early ASPH 35mm Summilux. Yes, it's true that technology has
> moved on, and that molded glass is now a greater possibility.
ASPH doesn't always equate to optimum performance, it is simply the best
option at the time, for instance the first Leica Noctilux was a 50f1.2, it
employed two hand ground ASPH lens elements and whilst a good performer
for its day it doesn't hold a candle to the current Noctilux 50f1 which has no
aspheric elements. The development of new glasses with special refractive
properties negated the need for the aspherics.
The new Leica APO Summicron-ASPH 90f2 has a ground aspheric element,
AFAIK Leica pioneered the blank moulding process, many of the lenses with
smaller elements ie the 35f1.4 and 35f2 employ these.
Cheers,
Rob Studdert
HURSTVILLE AUSTRALIA
Tel +61-2-9554-4110
Fax +61-2-9554-9259
UTC(GMT) +10 Hours
[EMAIL PROTECTED]
http://www.ozemail.com.au/~distudio/publications.html
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