Archived posting to the Leica Users Group, 2007/03/12

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Subject: [Leica] Re: LUG Digest, Vol 34, Issue 231: ASPH vs. Aspherical
From: don.dory at gmail.com (Don Dory)
Date: Mon Mar 12 19:05:56 2007
References: <C68A5EE3-304C-4475-9661-FD5246686067@btinternet.com> <C21AF5D2.489CF%mark@rabinergroup.com>

Mark,
It was a variant of computer controlled grinding.  Better control and much
tighter tolerances.

Enjoy

On 3/12/07, Mark Rabiner <mark@rabinergroup.com> wrote:
>
> On 3/11/07 2:45 PM, "Frank Dernie" <Frank.Dernie@btinternet.com> typed:
>
> > Aha, at the time I read that Leica had gone from ground to hot
> > pressing (in a Leica leaflet) the 90mm asph did not yet exist.
> > Anyway, as you say, it is the cost which differs. This was the point
> > I was trying to make - asph lenses are not necessarily dearer than
> > spherical when the aspheres are pressed rather than ground and the
> > aspherical surface simplifies the rest of the optics.
> > Frank
> >
> >
> > On 11 Mar, 2007, at 18:16, Sander van Hulsenbeek wrote:
> >
> >
>
> But I'd heard they'd stop doing the hot pressing and gone on to something
> else. "laser" beams probably. CGN CNR CRC something like that.
> Had to do with the glass; getting it from Hoya. They didn't like that.
> They can still do it cheaply relatively speaking of course as the prices
> on
> ASPH's didn't go up but they have another way of doing it. High tech and
> cutting edge as I recall but just now hot press.
> And if no one else heard this than maybe I dreamt it I'm surprised no one
> else is chiming in.
>
> But I seem to recall a discussion at the Leica factory a few months back
> about 5 people standing around with Christian Erhardt in a hallway, could
> have been a jet lagged hallucination.
>
> Mark Rabiner
> 8A/109s
> New York, NY
>
> markrabiner.com
>
>
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information
>



-- 
Don
don.dory@gmail.com

Replies: Reply from mark at rabinergroup.com (Mark Rabiner) ([Leica] Re: LUG Digest, Vol 34, Issue 231: ASPH vs. Aspherical)
In reply to: Message from Frank.Dernie at btinternet.com (Frank Dernie) ([Leica] Re: LUG Digest, Vol 34, Issue 231: ASPH vs Aspherical)
Message from mark at rabinergroup.com (Mark Rabiner) ([Leica] Re: LUG Digest, Vol 34, Issue 231: ASPH vs. Aspherical)