Archived posting to the Leica Users Group, 1999/01/24

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Subject: [Leica] Glass? Who said anything about GLASS ASPH?
From: Lucian Chis <chis@ece.orst.edu>
Date: Sun, 24 Jan 1999 16:17:32 -0800 (PST)

If I am not mistaking, the cost of older ASPH lenses was dictated by GLASS
aspherical elements whereas newer ASPH have PLASTIC molded aspherical
elements. Even for Leica. I don't know the particulars, but I would think
you can't get the same refringency index from plastic as from heavy glass
(glass with rare earth components).
What do you guys know of this?

Lucian

On Sun, 24 Jan 1999, Mark Rabiner wrote:

> Pascal wrote:
> > 
> > On 22-01-1999 02:32 Jim Brick wrote:
> > 
> > >Leica does not make their own glass (except for R&D) and Leica buys
> > >standard "off the shelf" glass from Hoya, Schott, and others. Standard
> > >glass catalog items. Eloquently dissertated to us by Erwin.
> > 
> > That's right: I have been told at Leica that they have four main
> > suppliers (two Japanese, one of them Hoya, and two European, one of them
> > Schott). And apparently the "special" glass would mainly come from the
> > European sources.
> > As for the polishing/grinding machines, many of them could be bought by
> > any lensmaker. 
> snip
> > 
> > Pascal
> 
> I don't know if Leica's new cheap ASPH's is something they have that the
> other guys don't.
> Are these lens grinding machines on the open market? I thought Leica
> developed these techniques.
> Mark RAbiner
>