Re: [Rollei] Rollei f3.5 Lenses

[Richard Knoppow <dickburk >]

At 08:17 PM 03/19/2001 -0800, you wrote:
>Hello Everyone-
>
>I see that the post-war Rolleis were furnished with a variety of f3.5
>lenses; the Tessar, or course, but also the Zeiss Jena Triotar, and the
>Schneider Xenars and Xenon.
>
>How do these lenses compare among each other? (leaving the Planar and
>Xenotar out of the discusion). Are the 3.5Tessar, Triotar, and Xenar
>essentially equivalent optics from different sources? Was the Xenon a
>premium offering relative to the other 3.5 lenses.
>
>Ed Balko
>Pleased to be using my f3.5 Automat again
>
  The Tessar is a four element lens and the Triotar a three element lens.
The performance of the Tessar is superior, at least at larger stops. The
Triotar was offered only on the Rolleicord, never on the 'flex. 
 The Schneider Xenar is a Tessar type lens. They were offered after WW-2
when Zeiss could not supply enough Tessars. While there is some
controversey (similar to the Planar-Xenotar thing) Xenars are probably the
equal of the Tessar, the ones I have are very sharp lenses. 
  Someone asked just today about Xenon lenses on Rolleis. AFAIK they were
never used, at least on production cameras. The Xenon is a fast Biotar (six
or seven element) lens. Most of them are f/2 or f/1.5 lenses for 35mm still
cameras and motion picture cameras. 
  There is one Rollei which used an f/2.8 Zeiss Biometar, a five element
lens similar (maybe identical) to the five element Planar but made at the
Jena factory and reputedly of excellent quality. 
  The advantage of a Biometar, Planar, or Xenotar is that its performance
is better when near wide open. Tessar type lenses have considerable coma
until stopped down about two stops from maximum. The more complex lenses
also do better when stopped down but are better near wide open. 
  Triotars, and other Cooke type triplets, tend to have over all spherical
aberration which results in a somewhat soft focus effect until stopped down
maybe three stops. The Tessar is condiderably better this way although a
good Triplet (and the Triotar was a good one) are quite sharp at around f/11.
  If Rollei did use a Xenon on other than a 35mm camera I would sure like
to know. I've managed to hide the appropriate volume of Prochnow from
myself (or else the Pixies are looking at it) so I can't double check. 
  BTW, I strongly suspect the Pixies since I found a long lost jack knife
this morning. They tend to trade things back and fourth. The Pixies who
hang around here are probably interested in photography and like to read my
books. I don't mind as long as I get them back. I have no idea of what they
needed the knife for but it was in good condition when returned.
- ----
Richard Knoppow
Los Angeles,Ca.
dickburk  

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