[rollei_list] Re: recoating and polishing the Xenotar lens
- From: Richard Knoppow <dickburk@xxxxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Tue, 12 Apr 2005 01:06:04 -0700 (GMT-07:00)
-----Original Message-----
From: Ruben <ruben@xxxxxxxxx>
Sent: Apr 11, 2005 10:44 PM
To: rollei_list@xxxxxxxxxxxxx
Subject: [rollei_list] Re: recoating and polishing the Xenotar lens
Thanks Richard,
The scratch was there when I got the camera off ebay - but i did not pay
more then 100 usd for it and asa long as she uses the hood/shade it does not
show on pictures ! I will leave it as it is untill I find a set of matched
view/take lens from a junked camera.
I know there is a lot of tessar/XENAR and Planar/Xenotar talk on these list
but so far I have not been able to see the difference between the tessar and
the Xenar - I took the same picture with both on the same fil and ames
setting and scanned them at 4000 dpi and they looked very much alike -
lovely both of them actually
I am getting more and more happy with my own tessar on the automat ! I t
gives my Leicas a hard run to the motifs!
I got another automat the 1956-7 with the coupling of EV values - the first
model - it has a tessar to but not the word "opton" as my 1951-1953
automat - are they the same lenses anyway ?
all the best Ruben
Opton was used for a time as a trademark for lenses made by the Zeiss
factory in Oberkochen. This was the result of legal action about who owned the
name "Zeiss". For at least a part of this time the original Zeiss plant in
Jena could not put the name Zeiss on its lenses. Marc Small can give you the
exact details and dates.
The quality of the lenses produced at the two parts of Zeiss were probably
similar but the detailed designs were probably not identical. Jena and
Oberkochen each had their own designers.
The Xenar is a Tessar _type_ lens but is an individual design. Actually,
both Zeiss and Schneider made several versions of these lenses over their
lifetimes.
The 5 element lens made by Zeiss as the Planar and by Schneider as the
Xenotar are similar but not the same. Actually Zeiss Oberkochen made at least
two versions of this lens and Zeiss Jena made another called the Biometar.
While there has been a long standing controversey about the relative merits of
these lenses they probably are closer in average performance than the
individual variation from lens to lens of any one type. The second Zeiss
version of the Planar was probably made to reduce the difficulty of making the
original which had a very steep and thin element cemented to another. Also, the
spacing between the front component and the second element is very small and
nearly touching so it must have been very critical.
The general opinion of the Xenar is that its the equal of the Tessar. I
have two Rolleis (cord and flex) with Xenars and both are very sharp lenses.
Actually, the one on the cord seems to be exceptional.
The f/2.8 Xenotar seems to be an exceptionally lens. I judge this because it
reproduces textures in a way typical of very good lenses on a larger format.
Also, this very fine detail holds up under magnification so its not an illusion
of some sort.
Before WW-2 Schneider was not known as a quality brand, after the war they
seemed to have turned the company around completely and made excellent lenses
with good quality control.
There has also been a lot of controversey about the relative quality of the
lenses made by the two halves of Zeiss. Because Zeiss headquarters, in Jena,
wound up in the Russian Zone, and because a number of key Zeiss personal
escaped to the U.S. Zone, two companies were formed, one in Jena and one in
Oberkochen. These were really independant but made similar products under the
same name. It is very difficult to judge the relative quality of the products
(lenses, microscopes, etc.), but both companies had problems due to the
aftermath of the war and the splitting up of the personel. Again, Marc is the
expert in this area and I am sure will correct any mistatements I may have
made.
I should say that Rollei bought lenses from all three suppliers. I think
Schneider was included because neither Zeiss could supply lenses at some point
and because Schneider had improved its quality so much.
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
Los Angeles, CA, USA
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