[rollei_list] Re: How rare is a Rollei with a Biometar?
- From: CarlosMFreaza <cmfreaza@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Sun, 4 Oct 2009 22:44:00 -0300
2009/10/4 Richard Knoppow <dickburk@xxxxxxxxxxxxx>:
>> Perhaps but the cemented surface in the Xenotar is plane or nearly so.
> There is a fairly thin meniscus negative element but and the apex of the
> inside lenses nearly touch the inside surfaces of the outside lenses.
> However, looking at various six element designs one finds the same very
> close spacing. The lens which seems to me to present difficulties in
> manufacture is the Planer. The front component is cemented and the outside
> part is negative meniscus with a _very_ thin center.
Richard, the Rolleiflex Planar five elements 2.8/80 and the Rolleiflex
Planar 3.5/75 five lements are two very different lenses about the
elements distribution and design, for the Planar 3.5/75 five elements
_the front component is not cemented_ it has a single first element
and a single second element, in the other hand the Planar 2.8/80 five
elements has the two front elements cemented, the bigger one has two
rear no cemented elements, the smaller one has three rear elements,
two of them are cemented, etc. The 3.5/75 Planar no cemented second
front element was divided into two thinner parts and then it became
with a second and third cemented elements, independent regarding the
first element, it became six elements; similar regarding the Xenotar
3.5./75 and Xenotar 2.8/80 five elements, despite both are more
similar than the two Planars five elements.
The Xenaotr 3.5/75 and the Planar 3.5/75 became very similar after
they got 6 elements.
My point is that it would be necessary to clarify about what kind of
Planar or Xenotar you are talking about regarding the lenses used on
the Rolleiflexes.
Carlos
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