Topogon

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Topogon
Richter-Zeiss Topogon (1933).svg
Introduced in1933
AuthorRobert Richter
Construction4 elements in 4 groups
Aperture6.3

Topogon is a wide field (originally 100 degrees field of view), symmetrical photographic lens designed by Robert Richter in 1933 for Zeiss Carl FA. [1] Lenses produced under the name Metrogon also cite the US patent of the Topogon design. The initial design patented by Richter was for a f=66mm f/6.3 lens, although the patent also contains two other refinements to the basic design, including one that used parallel elements to minimize vignetting. [1]

Field of view extent of the observable world seen at any given moment

The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation.

Photography Art, science and practice of creating durable images by recording light or other electromagnetic radiation

Photography is the art, application and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed in many fields of science, manufacturing, and business, as well as its more direct uses for art, film and video production, recreational purposes, hobby, and mass communication.

Lens (optics) optical device which transmits and refracts light

A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis. Lenses are made from materials such as glass or plastic, and are ground and polished or molded to a desired shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called lenses, such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses.

Topogon lenses have been produced with maximum apertures ranging from f/3.5 to f/15 in various focal lengths. [2] According to Richter, the Topogon was developed from the earlier Hypergon. [3] [4] Although the Hypergon covered a wide angle of view (140°) and had good flatness of field and distortion characteristics, the maximum aperture was limited to f/22 to control longitudinal spherical aberration and chromatic aberration. A new computation of a "fast" Hypergon was made by limiting the angle of view to 90°, increasing maximum aperture to f/6.3. The Topogon was then derived from the "fast" Hypergon by adding a second set of strongly curved meniscus elements inboard of the larger spherical elements to correct longitudinal spherical aberration. [5]

The focal length of an optical system is a measure of how strongly the system converges or diverges light. For an optical system in air, it is the distance over which initially collimated (parallel) rays are brought to a focus. A system with a shorter focal length has greater optical power than one with a long focal length; that is, it bends the rays more sharply, bringing them to a focus in a shorter distance.

Angle of view angular extent of a given scene that is imaged by a camera

In photography, angle of view (AOV) describes the angular extent of a given scene that is imaged by a camera. It is used interchangeably with the more general term field of view.

Distortion (optics) deviation from rectilinear projection (optics)

In geometric optics, distortion is a deviation from rectilinear projection; a projection in which straight lines in a scene remain straight in an image. It is a form of optical aberration.

The Topogon was later developed into the Pleogon lens by Richter and Friedrich Koch in 1956. [6] The Pleogon, used for photogrammetry, used a cemented achromatic lens just ahead of the central stop and added two meniscus groups on either side to maintain lens symmetry. [5]

Photogrammetry The science of making measurements using photography

Photogrammetry is the art and science of making measurements from photographs, especially for recovering the exact positions of surface points. Photogrammetry is as old as modern photography, dating to the mid-19th century and in the simplest example, the distance between two points that lie on a plane parallel to the photographic image plane, can be determined by measuring their distance on the image, if the scale (s) of the image is known.

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Angénieux retrofocus

The Angénieux retrofocus photographic lens is a wide-angle lens design that uses an inverted telephoto configuration. The popularity of this lens design made the name retrofocus synonymous with this type of lens. The Angénieux retrofocus for still cameras was introduced in France in 1950 by Pierre Angénieux.

Carl Zeiss AG German manufacturer of optical systems

Carl Zeiss , branded as ZEISS, is a German manufacturer of optical systems, and industrial measurement and medical devices, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe and Otto Schott they built a base for modern optics and manufacturing. There are currently two parts of the company, Carl Zeiss AG located in Oberkochen with important subsidiaries in Aalen, Göttingen and Munich, and Carl Zeiss GmbH located in Jena.

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Ludwig Bertele German inventor

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Hologon

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References

  1. 1 2 US 2031792,Robert Richter,"Anastigmatic objective for photography and projection",issued February 25, 1936, assigned to Carl Zeiss
  2. Cavina, Marco. "Hypergon - Topogon - Russar - Biogon - Aviogon - Hologon: La storia definitiva dei super-grandangolari simmetrici" [Hypergon - Topogon - Russar - Biogon - Aviogon - Hologon: The definitive history of the super-wide angle symmetric lenses]. Retrieved 8 November 2018.
  3. In the paper, Richter attributed the Hypergon design to Emil von Höegh; the 1900 patent for the Hypergon is credited to Carl Paul Goerz, a frequent collaborator with von Höegh.
  4. USGrant 706640,Carl Paul Goerz,"Astigmatically-corrected wide-angle objective",issued 12 August 1902, assigned to Carl Paul Goerz
  5. 1 2 Richter, Robert (December 1956). "Development and Perfection of the Topogon Lens" (PDF). Photogrammetric Engineering & Remote Sensing. XXII (5): 868–874. Retrieved 9 November 2018.
  6. DEApplication 1097710,Dr Robert Richter&Friedrich Koch,"Anastigmatisches lens", assigned to Carl Zeiss SMT GmbH