[rollei_list] Re: 2.8 80mm Opton-Tessar
----- Original Message ----- From: "Carlos Manuel Freaza" <cmfreaza@xxxxxxxxxxxx> 
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Thursday, November 16, 2006 3:15 AM
Subject: [rollei_list] Re: 2.8 80mm Opton-Tessar



Richard, the Tessar for the Baby was a 2.8/60 and for
the 4x4 format, I mentioned this lens in one of my
posts, I guess that the prescriptions are different.
It would  be interesting to know why the baby 2.8/60
was not manufactured after the war, only the 3.5/60
version, if the lens was so good it would be better to
choose the 2.8/60 and not the 3.5/60.-

All the best
Carlos
By the same token we don't really know what the prescriptions are for any of the Rollei Tessars. I have patents that I _think_ are the f/2.8 Biometar, Planar, and Xenotar but I am only guessing given the dates and lack of patent references to similar designs. Zeiss has a great many Tessar designs, evidently they kept working on it. Which, if any, of these designs ever reached production I have no idea. While its certainly possible the f/2.8, 60mm lens left something to be desired its also possible to think of alternative reasons for dropping it. Cost may have been a consideration, or the shutter (larger one needed). In any case f/3.5 Tessars tend to be better than f/2.8 ones and those around f/10 even better. Other designs offer better performance at large apertures, so we have five and six element lenses on Rollei TLRs and even more elaborate lenses on other cameras. I suppose there must have been business records at Rollei which would give definite answers to some of the questions we are asking but its quite possible they no longer exist. I expect some of the records to have been destroyed during the war and perhaps others after the war on the basis that they were expensive to keep and of no business use. The later has become typical for modern businesses, which, for the most part, have no sense of or interest in their history. It is possible to measure the performance of actual lenses using various optical measurement techniques. Some are fairly simple requiring no more than a decent optical bench, others require special, computer controlled, instruments. Such measuements on a reasonably sampling of lenses could decide such perenial questions as whether the Planar or Xenotar is better, if the Xenar is the equal or even the superior of the Tessar. Do Tessars in Rollei cameras of varous ages all come from the same design or is there more than one design represented, what was wrong with the Jena f/2.8 Tessars (assuming some can be found) and etc, etc,. This would be a major project since one would have to assemble the samples and arrange for properly controlled measurements to be made somewhere where the validity of the measurements would be beyond question. When I win the lottery and become disgustingly rich I may consider such a project, but, as long as I must be careful of grocery bills it will have to wait until some other angel comes along. The only comfort I can think of is that its very doubtful if anyone will be interested in tracking the history of the digital cameras of our day in seventy or eighty years. 
  Heigh-ho, its time to try to sleep.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 
---
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