From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 06/02/03-04:20:08 PM Z
----- Original Message -----
From: "Tor-Einar Jarnbjo" <tor-einar@jarnbjo.de>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Monday, June 02, 2003 2:40 PM
Subject: RE: Age of Rodenstock lens
>
> > Given the likely volume of lenses made the list makes
> > sense but the age given by phone does not.
> > I suspect the lady at Rodenstock either got the number
> > wrong or read the list wrong. Perhaps an extra digit got
> > inserted. If she interpreted the serial number as, say,
> > 370023, the 1930 date would be right. I strongly suspect
> > this is what happened.
>
> The estimate was based on the lens type/brand and not on
the serial number.
> But of course, the man may have made a mistake. I would
also have dated the
> lens much older than 1930 based on the "look", but who
knows. Perhaps
> someone here knows anything about this Bistigmat 13x18cm
large format lens?
>
> Tor
>
I am confused. I've received mail from two sources
evidently about the same lens. This seems to be another
lens, is it? Who is the manufacturer?
I don't find the name Bistigmat in a quick search, not
listed as a Rodenstock name although they made a Biplanat.
The "stigmat" part of the name suggests an anastigmatic
lens, if so, this would indicate it was made after the
development of "Jena" glass in 1885. While it is possible to
make an chromatically corrected anastigmatic lens with "old"
glass this was not known until long after the new Barium
crown glasses were introduced. The Busch Omnar, designed by
Martin, a four element air spaced lens of the "Homocentric"
type is made with all old type glass.
Again, you can often tell at least something about the
construction of a lens by counting reflections.
--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com
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