[rollei_list] Re: Planar, Xenotar, Summicron

  • From: Marc James Small <msmall@xxxxxxxxxxxx>
  • To: rollei_list@xxxxxxxxxxxxx
  • Date: Sun, 29 May 2005 22:22:12 -0400

At 04:42 PM 5/27/05 +0100, FRANK DERNIE wrote:
>According to the Canon Lens Work books, which are
>interesting and inexpensive, they point out that Canon
>uses 4 types of aspherical elements. The largest have
>to be ground, then there are hot moulded using metal
>masters (I believe Leica use ceramic masters to mould
>their aspherics), replicated which I believe is a thin
>plastic aspheric layer moulded onto a spherical glass
>element and plastic moulded.
>Some are for quality, some for miniturisation. I don't
>have the books to hand so may not be quoting
>perfectly.

Frank

Leica uses the Docter Optic moulding technology under license.  Docter is
now a subsidiary of Jenaer Glasswerke, the Zeiss-controlled successor to
the orginal Schott Factory.

Marc

msmall@xxxxxxxxxxxx=20
Cha robh b=E0s fir gun ghr=E0s fir!

NEW FAX NUMBER:  +540-343-8505



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