[rollei_list] Re: OT: Xenar
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Fri, 23 Sep 2005 14:18:26 -0700
----- Original Message -----
From: "J Patric Dahlén" <jenspatricdahlen@xxxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Friday, September 23, 2005 1:56 PM
Subject: [rollei_list] OT: Xenar
>From: Peter J Nebergall:
I have a Rolleicord with 3.5 Xenar, 75mm. I also have
seen a # of 35mm
examples of this lens, most notable on German Kodaks
(Retinas) where it
is often standard. Is this the same optic?
Yes. There were five element 2,8 Xenars too before the
war, in 50 and 75 mm. The 2,8/50 Xenon on the pre-war
Retinas were actually Xenars of this type.
/Patric
---
Rollei List
I think yor are refering to five element Tessar type
lenses rather than the Xenotar type, which was based on work
done by C.G.Wynne of Wray in England. Wray's work was done
c.1944.
The Xenotar is, essentially, a modification of the Biotar
type where two elements are combined into one. The lens
still has the essential symmetry of the Biotar. There were a
number of Tessar type lenses with three cemented elements in
the rear, Schneider made at least one. Zeiss had a 6 element
Tessar called the Biotessar with three cemented elements in
back and two in front. I suppose it could also be considered
a Heliar type. Bausch & Lomb made an arial lens with three
cemented elements in the rear, other lenses were the Ross
Xpres (not the W.A.Xpres, which is a Plasmat) and the
Gundlach Radar. The Radar was probably designed to avoid the
Zeiss Tessar patent rather than to improve the correction.
In any case, the idea of adding an element was tried by
several makers. It would seem that other designs were more
successful in providing improved performance.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
---
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