Difference between revisions of "Dagor"

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The '''Dagor''' was [[Goerz]]'s most renowned lens construction, a symmetrical [[Anastigmat]] with 6 elements in two groups. It was designed by Emil Von Höegh who also had tried to win [[Zeiss]] as its maker. In 1892, after Zeiss' negative reply, he had luck that he could replace the chief lens designer of Goerz who had recently died.
 
The '''Dagor''' was [[Goerz]]'s most renowned lens construction, a symmetrical [[Anastigmat]] with 6 elements in two groups. It was designed by Emil Von Höegh who also had tried to win [[Zeiss]] as its maker. In 1892, after Zeiss' negative reply, he had luck that he could replace the chief lens designer of Goerz who had recently died.
  
''Dagor'' was the abbreviation for "Doppel-Anastigmat GOeRz". Production licences were given to lens maker [[Ross]] in London and optician Karl Fritsch in Vienna.
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The lens was first made as the '''Doppel Anastigmat Series III''', and renamed Dagor in 1904.<ref name=G>Greenleaf, A.R. (1950) ''Photographic Optics''. Macmillan, New York. p 71.</ref> ''Dagor'' is an abbreviation of "Doppel-Anastigmat GOeRz". The original patent describes an f/8 lens;<ref>[http://worldwide.espacenet.com/publicationDetails/originalDocument?CC=DE&NR=74437C&KC=C&FT=D&ND=3&DB=worldwide.espacenet.com&locale=en_EP German Patent 74437], ''Sphärisch, chromatisch und astigmatisch corrigirtes Objectiv'', filed 1892 and granted 1894 to C.P. Goerz, at [http://worldwide.espacenet.com/?locale=en_EP Espacenet], the patent search facility of the European Patent Office. </ref> Dagors were later made as f/6.8 in shorter focal lengths, and f/7.7 in longer ones.<ref name=G/> The patent describes two different designs: one in which each cemented half of the lens is a pair of positive lenses enclosing a negative one (this is the Dagor), and another in which each half is a pair of negative lenses enclosing a positive one; this is the general design used at about the same time by [[Steinheil]] for the Orthostigmat. [[Voigtländer]]'s Collinear is the same.<ref name=G/> Production licences were given to lens maker [[Ross]] in London and optician Karl Fritsch in Vienna.
  
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|image_text= [[Zeiss]]-made Goerz Dagor on [[Idea Spring|Rokuoh Sha Idea Spring]] (1930)
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==Notes==
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<references/>
  
 
==Links==
 
==Links==
 
*[http://books.google.com/books?id=OJrJrEJ-r9QC&pg=PA243&lpg=PA243&dq=Emil+Von+Hoegh about Von Höegh] on Google, excerpt from "A history of the photographic lens" of Rudolf Kingslake
 
*[http://books.google.com/books?id=OJrJrEJ-r9QC&pg=PA243&lpg=PA243&dq=Emil+Von+Hoegh about Von Höegh] on Google, excerpt from "A history of the photographic lens" of Rudolf Kingslake
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*[https://www.flickr.com/groups/1512213@N20/pool/ Flickr group]
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[[Category:Goerz]]
 
[[Category:Goerz]]
 
[[Category:German lenses]]
 
[[Category:German lenses]]
 
[[Category:1890-1899]]
 
[[Category:1890-1899]]

Revision as of 09:18, 18 January 2017

The Dagor was Goerz's most renowned lens construction, a symmetrical Anastigmat with 6 elements in two groups. It was designed by Emil Von Höegh who also had tried to win Zeiss as its maker. In 1892, after Zeiss' negative reply, he had luck that he could replace the chief lens designer of Goerz who had recently died.

The lens was first made as the Doppel Anastigmat Series III, and renamed Dagor in 1904.[1] Dagor is an abbreviation of "Doppel-Anastigmat GOeRz". The original patent describes an f/8 lens;[2] Dagors were later made as f/6.8 in shorter focal lengths, and f/7.7 in longer ones.[1] The patent describes two different designs: one in which each cemented half of the lens is a pair of positive lenses enclosing a negative one (this is the Dagor), and another in which each half is a pair of negative lenses enclosing a positive one; this is the general design used at about the same time by Steinheil for the Orthostigmat. Voigtländer's Collinear is the same.[1] Production licences were given to lens maker Ross in London and optician Karl Fritsch in Vienna.



Notes

  1. 1.0 1.1 1.2 Greenleaf, A.R. (1950) Photographic Optics. Macmillan, New York. p 71.
  2. German Patent 74437, Sphärisch, chromatisch und astigmatisch corrigirtes Objectiv, filed 1892 and granted 1894 to C.P. Goerz, at Espacenet, the patent search facility of the European Patent Office.

Links