Archived posting to the Leica Users Group, 1999/09/13

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Subject: Re: Re[2]: [Leica] Plastic Aspheric Lens Elements
From: "Ken Iisaka" <kiisaka@ibm.net>
Date: Mon, 13 Sep 1999 22:43:52 -0700

Art,

Certainly, Leitz ground its two aspherical surfaces for the original
Noctilux 1:1.2/50.  Canon too grinds aspherical elements for a number of its
lenses, and Nikon for the aforementioned Noct-Nikkor, and according to
various rumours, the tank-like 300mm 1:2 lens.  A friend of mine who shall
remain nameless who works for Nikon has told me that the Noct-Nikkor lens
craftsman pretty much ground the front element by hand, then checking his
work with a master, observing the resultant Newton rings.

Only a small number of glass can be moulded, and the diameter is quite
limited.

- ----- Original Message -----
From: Art Sala <artsala@earthlink.net>
To: <leica-users@mejac.palo-alto.ca.us>
Sent: Monday, September 13, 1999 7:49 PM
Subject: Re[2]: [Leica] Plastic Aspheric Lens Elements


Ken:

I heard that Zeiss is the only lens manufacturer that has the ability
to grind glass aspheric elements.  Then again, I don't know if it matters
(photographically speaking)  whether the aspheric element is ground glass,
moulded plastic or some sandwiched hybrid.  Maybe some other lug lens
guru can give more technical insight.