[rollei_list] Re: Rolleiflex Planar 3.5/75 6 elements patent
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Mon, 5 Oct 2009 20:09:16 -0700
----- Original Message -----
From: "CarlosMFreaza" <cmfreaza@xxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Monday, October 05, 2009 5:39 PM
Subject: [rollei_list] Rolleiflex Planar 3.5/75 6 elements
patent
I found the US Patent for the 3.5/75 6 elements "Planar" as
used in
the Rolleiflex from about 1960, it looks like a Xenotar
design clearly
and the diagram is identical regarding the diagram Todd
sent me and
regarding that one in Prochnow, the only minimal
difference is the
very slight separation between the fourth and fifth
element in the
patent that are cemented in the other diagrams. This lens
was patented
in Germany in February 1955 for Carl Zeiss and in February
1956 in the
States for Carl Zeiss too.
Look for the Patent number: 2831397 at Google patents.-
Carlos
---
This patent describes an f/2 lens. Whether it has any
relationship to the five element Planar is open to question.
One would have to analyse the elements given in the patent.
It could as well be a conventional Planar with one element
split into two, a common device for reducing aberrations.
Kingslake points out somewhere that with computer design its
difficult to describe any lens as being related to older
generic types. Note that a similarity in the schematic
diagram can be misleading as to the functions of the
elements in a particular design.
--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
---
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