[rollei_list] Re: Identifying 2.8F models...the 3.5/75 six elements (again)

  • From: Jerry Lehrer <jerryleh@xxxxxxxxxxx>
  • To: rollei_list@xxxxxxxxxxxxx
  • Date: Mon, 02 Jan 2006 20:12:12 -0800

Peter,

That "secondary tier" expression of yours is bound to piss off
a few folks, you Troll!

Jerry

"Peter K." wrote:

> Todd, you are reaching with this. OK, so it does not specifically
> states it was done to IMPROVE performance. It DOES state that it was
> done to meet the guaranteed performance of the 75mm lens. So if we are
> saying it was difficult to meet the criteria or a certain level of
> performance, wouldn't that mean basically the newer design improved
> things? Hence, there would have been a better chance of getting a
> better performing 75mm lens. More than that I do not know. But I
> cannot imagine anyone in business stating that the newer design
> IMPROVED the performance because they are saying the older lenses are
> not as good. As to the 5-element being used for 7 years, I do not
> know. Since this was a secondary tier camera, perhaps Rollei felt it
> was not necessary to change it and allowed them to better
> differentiate the F model. Just my opinion on the last part. Peter
> K On 1/2/06, todd belcher <todd_belcher@xxxxxxxxx> wrote:
>
>      Actually your analysis of the text does not support your
>      claim that the 6 element lens was done for an increase in
>      performance. Nowhere in the quoted passage does it say "the
>      6-element version were done to IMPROVE the performance of
>      the 3.5 model". It does say maintaining quality on 5
>      elements was difficult. This could have been because one of
>      the glass types in the 5 element became expensive, or
>      unavailable, and thus maintaining the 5 element design with
>      the same performance would have been difficult. Remember the
>      3.5 E came out in 1956 with the same five element lens and
>      it wasn't until sometime around 1963 that the six element
>      lens was introduced. So that means about 7 years of five
>      element 3.5 gauss type lenses. I cannot imagine Rollei
>      would  allow such a long time to pass for supposedly
>      underperforming lenses. Therefore, the switch to 6 elements,
>      guaranteed the SAME (it says "served to MEET the performance
>      data guaranteed to Rollei") quality as the 5 element lens.
>      And as a bonus, it happened to cost the same as the 5
>      element lens. todd   On 2-Jan-06, at 3:02 PM, Peter K.
>      wrote:
>
>     > OK Carlos, I have the Rollei 75 Years book, also written
>     > by Prochnow. On pages 140 and 141 it stated the following
>     > with regard to the model F: "Of course there were other
>     > improvements that had their share in the great success of
>     > the "F" models. One of these was the new, six-element
>     > Planar 75mm F3.5 lens which was introduced rather quietly
>     > with the third version of the 3.5F. Shortly after,
>     > Schneider followed with a 75mm Xenotar F3.5, likewise made
>     > up of six elements. The new optical formulas served to
>     > meet the performance data guaranteed to Rollei, which were
>     > difficult to attain with only five element. Production
>     > costs remained unchanged. The 80mm F2.8 Planar and Xenotar
>     > lenses did not have these problems and thus retained their
>     > five elements." So here is a book endorsed by Rollei and
>     > written by Prochnow where he claims the 6-element version
>     > were done to improve the performance of the 3.5 models and
>     > the interesting note is that it is clearly stated that
>     > PRODUCTION COSTS REMAINED UNCHANGED. This is why I stated
>     > this. Peter K
>     >  On 1/2/06, Carlos Manuel Freaza <cmfreaza@xxxxxxxxxxxx >
>     > wrote:
>     >
>     >      Excuse me Peter, I have the Rollei Report II and
>     >
>     >      Prochnow does not write about resolving power
>     >      problems
>     >      for the five elements 3.5/75,and in his message
>     >      to me,
>     >      he insisted that the Planar and Xenotar six
>     >      elements
>     >      were cheaper to manufacture than the five
>     >      elements and
>     >      this was the only reason to provide the
>     >      Rolleiflex
>     >      with this six elements 3.5/75 Planar and
>     >      Xenotar;
>     >      Richard K.also suspected this economical reason
>     >      before
>     >      I received the message from Prochnow and the
>     >      lens
>     >      designer friend of Richard K also wrote about
>     >      these
>     >      economical reasons agreeing with Richard.
>     >      If you see the second element for the five
>     >      elements
>     >      Planar 3.5/75 and the fourth element for the
>     >      Xenotar
>     >      3.5/75, they are a thick glass piece, a
>     >      divergent
>     >      meniscus (negative lens); for the six elements
>     >      version
>     >      this piece or element was divided into two
>     >      thinner
>     >      pieces and cemented maintaining its condition of
>     >
>     >      divergent meniscus and occupying the same place
>     >      regardiong the original divergent meniscus, the
>     >      other
>     >      elements are identical for the five and six
>     >      elements
>     >      versions and then they are (the five and six
>     >      elements)
>     >      the same lens in practical use.
>     >      I owned a 3.5E  provided with a Planar five
>     >      elements
>     >      several years and it was an outstanding lens for
>     >
>     >      50x50cm enlargements.-
>     >
>     >      All the best
>     >      Carlos
>     >      PS:Peter, if necessary, I have the question and
>     >      the
>     >      Prochnow's answer.-
>     >      --- "Peter K." < peterk727@xxxxxxxxx> escribió:
>     >
>     >      > Yes Carlos I know. In his book however,
>     >      Prochnow
>     >      > claimed, or used, the party
>     >      > line that it was for resolving power. May
>     >      actually
>     >      > be a combination of the
>     >      > two.
>     >      >
>     >      > Peter K
>     >      >
>     >      >
>     >      > On 1/2/06, Carlos Manuel Freaza
>     >      > <cmfreaza@xxxxxxxxxxxx > wrote:
>     >      > >
>     >      > > --- "Peter K." < peterk727@xxxxxxxxx>
>     >      escribió:
>     >      > > > >.... The 3.5 version of this
>     >      > > > model also received a newly designed
>     >      Planar lens
>     >      > of
>     >      > > > six elements, followed
>     >      > > > by a new Schneider 3.5 Xenotar with six
>     >      > elements.
>     >      > > > This was allegedly to
>     >      > > > improve the resolving power since F & H
>     >      were of
>     >      > the
>     >      > > > opinion that the older
>     >      > > > style 5-element 3.5 lenses did not live up
>     >      to
>     >      > > > expectations....
>     >      > > > Peter K
>     >      > >
>     >      > > According Claus Prochnow Rollei Report II
>     >      and a
>     >      > > message he wrote me answering my specific
>     >      question
>     >      > > about it, the change for a Planar and
>     >      Xenotar
>     >      > 3.5/75
>     >      > > from five elements into six elements had
>     >      > economical
>     >      > > reasons only, the Planar and Xenotar five
>     >      elements
>     >      > > 3.5/75 had a thick element very expensive to
>     >
>     >      > > manufacture and then this element was
>     >      converted
>     >      > into
>     >      > > two thinner elements without a real change
>     >      for the
>     >      > > lens general design, you can clearly see it
>     >      > comparing
>     >      > > both lenses five and six elements diagram .
>     >      > > Prochnow writes in his book that the six
>     >      elements
>     >      > > Planar and Xenotar 3.5/75 were "cheaper" to
>     >      > > manufacture "maintaining the lens quality"
>     >      (in
>     >      > other
>     >      > > words, the five elements was at least equal
>     >      > regarding
>     >      > > quality).
>     >      > > He also writes that the Planar and Xenotar
>     >      2.8/80
>     >      > have
>     >      > > not production costs problems and then they
>     >      were
>     >      > > maintained without changes.-
>     >      > >
>     >      > > All the best
>     >      > > Carlos
>     >      > >
>     >      > >
>     >      > >
>     >      > >
>     >      > >
>     >      > >
>     >      > >
>     >      > >
>     >      > >
>     >      > >
>     >      > >
>     >      >
>     >      _
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>     >      > --
>     >      > Peter K
>     >      > Ó¿Õ¬
>     >      >
>     >
>     >
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>     > --
>     > Peter K
>     > Ó¿Õ¬
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> Peter K
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