[rollei_list] Re: Schott Glass
- From: CarlosMFreaza <cmfreaza@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Tue, 10 Aug 2010 07:15:09 -0300
2010/8/10 Marc James Small <marcsmall@xxxxxxxxxxx>:
> Not to argue with you over your fine answer, but these glasses from "other
> suppliers" were glasses supplied under the Schott Catalogue. Schott
> publishes an annual guide to its optical glasses, listing the basic
> performance. For some decades, Schott has farmed out the more routine
> glasses to other manufacturers such as Hoya, and those ordering such glasses
> from Schott will have the orders filled by Hoya lens blanks. We had a nice
> discussion of this over on the Leica Users' Group some years back, when the
> LUG was still film-oriented. None of this means that a Hoya-supplied glass
> is not a Schott glass: it is a glass made under license by Hoya to Schott
> specifications. Such was the case with Rollei Singapore: I suspect that
> all of the optical glasses used there came from Oriental sources, primarily
> Hoya, with a few other glassworks, working to Schott specifications,
> included as well.
It was mentioned in my post the Schott Catalogue, "...which is a
standard reference for the properties of the many optical glasses
produced by them and other companies...". The more expensive lenses
made in Singapore were made with Schott glass, the cheaper ones with
Hoya glass.
The Japanese Ohara is a significant glass provider too (under Schott
specs) but they are not mentioned for Singapore.
> I am uncertain why you added the piece on the production of lenses at
> Braunschweig. No one on this List has denied that Rollei makes lenses and
> that it has done so since at least 1973. Any lens marked "Carl Zeiss HFT
> Germany" is a Rolleiflex product made in Braunschweig, under license from
> Zeiss at Oberkochen.
You denied the List knowledge about Schott, the comment's author about
Rollei lenses was Kornelius J. Fleischer (Carl Zeiss CEO during some
years), he mentions Rollei used Schott glass at Braunschweig.
Not all the lenses “Carl Zeiss HFT Germany” for the SL 35 system were
made by Rollei, lenses made in Oberkochen also were engraved “HFT”
after to receive the CZ T* multicoating, it happened because the first
lenses that CZ made for the SL 35 with the T* process were not marked
indicating this process in the lens ring (the T* process was new at
the time), Rollei became desperate because Japanese lenses with MC
process had this feature engraved with big letters in the lens ring
and then Rollei started to engrave “HFT” (High Fidelity Transfer) the
multicoated lenses made by CZ that CZ did not still engrave “T*”.
Carl Zeiss liked very much the term “HFT” and when they started to
engrave their lenses with “T*”, they keep the term “HFT” for the
lenses made for the SL35 system that received the “T*” process saying
the Rollei SL 35 lenses were already known that way. The lenses made
by Rollei are engraved “made by Rollei” and “HFT” if they have the HFT
process; lenses made by Carl Zeiss are engraved “Carl Zeiss Germany “
or “Carl Zeiss West Germany” and “HFT” if they received the “T*”
process in Oberkochen and always talking about lenses made for the
SL35 system. Photographs about the different samples are shown in the
Rollei Report IV.
> One of the reasons that Zeiss has restricted production of the exotics to
> Oberkochen is the need for exotic glasses in these exotic lenses, and those
> are all supplied by Schott-Mainz.
>
> Marc
Carlos
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