[LargeFormat] cult lenses

[Richard Knoppow]

----- Original Message ----- 
From: "Dan Kalish" <kaliushkin@att.net>
To: <rollei-digest@mejac.palo-alto.ca.us>;
<rollei@mejac.palo-alto.ca.us>; "LF listserv submission"
<largeformat@f32.net>
Cc: "Kalish, Dan" <kaliushkin@postoffice.worldnet.att.net>
Sent: Monday, June 02, 2003 8:41 AM
Subject: [LargeFormat] cult lenses


> What are Dagor, Cooke, Dallmeyer, Goerz, Dallmeyer, and
Wollensak lenses and
> why are they held in such reverence?  I was checking out
Dagor77's auctions.
> What a character!
>
> Dan Kalish
> Flushing, New York, New York, USA
>
  Just to clarify, Dagor is the name of a lens type made by
Goerz. The other names are manufacturers. Each made a
variety of lenses.
  Goerz began as a German company. The Dagor was offered to
them by its designer, Emile von Hoegh, after he had
approached Zeiss and others. Goerz began manufacturing it
and it turned out to be very successful. After WW-1 (1926)
Goerz was forced to merge into the Zeiss-Ikon combination
during the very severe economic depression which followed
the war. Zeiss continued making Dagors under the Zeiss-Goerz
name.
  Goerz had also established US branch about 1899. This
company became independant, probably at the outbreak of the
war, but I don't have definite history. Goerz American
Optical (not to be confused with the American Optical
Company), made Dagor, Dogmar, and Aprochromatic Artar
lenses, and some other, based on the German Goerz designs.
Goerz lenses are noted for high quality of manufacture.
  It is the Apochromatic Artar which was designed for
photomechanical plate making. Some special Dagors were
designed about the early 1950's for use in making
photo-lithographic plates, where a wide angle lens is
desirable. While well corrected for color these are not
apochromatic lenses. These were sold as Trigor and Blue-Dot
Dagor, two names for the same lens.
  Goerz American was sold several times after the mid 1950's
and was eventually aquired by Schneider (1971). Schneider
continued to make the Apo Artar and contracted with Kern of
Switzerland to make some Dagors. These seem to have been
re-designed and were sold as Gold-Dot Dagors. These lenses
often command high prices on the used market. The Golden
Dagor, sometimes wrongly called a Gold Rim Dagor, was the
same design as earlier Dagors but sold with a polished brass
front cell. These are c.late 1950's. It was a marketing
gimmick.
  Wollensak was an old line US company started by the
Wollensak brothers, two German immigrants who originally
worked for Bausch & Lomb. The began in business for
themselves selling shutters of superior quality. Eventually
they entered the lens market. Wollensak shutters are
excellent but their lenses are of variable quality. Some are
excellent, some are dogs. They made a line of soft focus
lenses in the 1930's and 40's (perhaps even earlier) which
were popular.
  Wollensak made a tremendous number of lenses under
contract for small camera manufacturers. They had a few
original designs but mainly made lenses of established
types.
  Cooke was a late entry into photographic lens making. The
name Cooke Triplet was applied to a lens of great importance
in lens design. It was designed by Harold Dennis Taylor, who
worked at the time for Cooke of York, a British company who
made mainly telescopes and optical instruments. Cooke did
not want to make photographic lenses at the time so Taylor
was allowed to take his design to Taylor, Taylor, and
Hobson, a highly respected English manufacturer of lenses
and optical instruments. The lens was named the Cooke lens
in honor of the originating company. Later, Cooke made
adjustable soft-focus lenses based on the Taylor Triplet
design. This design has recently been resurrected and new
Cooke soft focus lenses are being offered by Cooke.
  Dallmeyer was also an English company despite the German
name. Dallmeyer was, along with Steinheil, the inventor of
the famous Rapid Rectilinear lens, called the Aplanat by
Steinheil. There has always been some controversey about
this design. Steinheil's lens was designed with the help of
von Seidel, a pioneer researcher in optical theory.
Dallmeyer had no such help but evidently the two designs
were arrived at independantly and each was issued a patent.
  Dallmeyer became well known later for introducing
telephoto lenses.
  While each of these companies made some excellent lenses
and while some may be collector's items, I don't think any
were of such outstanding quality as to command unusually
high prices.
 Dagors have always been popular because they are
essentially wide angle lenses. They are quite sharp when
stopped down but the type suffers from a large amount of
zonal spherical aberration, resulting in some focus shift
when stopping down. The same spherical gives the lens a
pleasant soft focus effect when used near wide open. Modern
Plasmat types have very much less zonal spherical. Dagors
are expensive to make because of the four cemented surfaces
which require a lot of extra steps in manufacture. All
cemented lenses like the Dagor and Series VII Zeiss Protar,
were designed long before lens coating was available to
control flare. Reducing the number of glass-air surfaces was
the only method open to the designer to keep flare down. Air
spaced elements offer much more freedom of design so lenses
with many cemented surfaces dissapeared when lens coating
became available.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com