Topogon

Topogon is a wide field (originally 100 degrees field of view), symmetrical photographic lens patented by Robert Richter in 1933 for Carl Zeiss AG.[1] As there are four meniscus elements in four groups, deployed symmetrically around the central aperture, it is considered a double Gauss lens variant.

Topogon
Introduced in1933
AuthorRobert Richter
Construction4 elements in 4 groups
Aperture6.3

Design

According to Richter, the Topogon was developed from the Goerz Hypergon (1900),[2] one of the first super-wide-angle lenses.[3] Richter credits the mathematician Emil von Höegh, who had designed the Dagor anastigmat (1892), with designing the Hypergon for Goerz. 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.[4]: 54–55  A new computation of a "fast" Hypergon was made by limiting the angle of view to 90°, which allowed an increased maximum aperture of f/6.3.[3]

The Topogon was derived from the "fast" Hypergon by adding a second, symmetric set of strongly curved meniscus elements inside the larger spherical elements to correct longitudinal spherical aberration.[3] The initial design patented by Richter was for a f=66mm f/6.3 lens covering 100°, although the patent also contains two other refinements to the basic design, including one that used parallel elements to minimize vignetting.[1] As the name suggests, the Topogon was intended to be used for topographical surveys and photogrammetry.[5]

The Topogon was later developed into the Pleon fisheye lens (1938)[6] and Pleogon lens by Richter and Friedrich Koch in 1956.[7] The Pleon was used for aerial surveillance during World War II, and was equipped with a large negative meniscus cemented group ahead of the Topogon core as an early example of an inverted telephoto design; a special projector was required to display an undistorted image.[8] 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.[3]

Topogon lenses have been produced with maximum apertures ranging from f/3.5 to f/15 in various focal lengths.[5]

  • Hypergon, Topogon, and Zeiss development
  • Goerz Hypergon by von Höegh (1900), from US 706,650
    Goerz Hypergon by von Höegh (1900), from US 706,650[2]
  • Zeiss Topogon by Richter (1933), from US 2,031,792
    Zeiss Topogon by Richter (1933), from US 2,031,792[1]
  • Zeiss Pleon by Richter (1938), from US 2,247,068
    Zeiss Pleon by Richter (1938), from US 2,247,068[6]
  • Zeiss Pleogon by Richter & Koch (1956), from DE 1,097,710
    Zeiss Pleogon by Richter & Koch (1956), from DE 1,097,710[7]

Influence
Topogon-design lens and auxiliary viewfinder for the Mamiya Press line of cameras

Goerz was merged into the Zeiss Ikon company in 1926.[9] An independent branch of Goerz in America, which had been established in 1895, licensed the Topogon design to Bausch & Lomb, who produced it as the Metrogon for the United States, citing the same US patent as the Topogon. The Metrogon was introduced in the early 1940s at the same cost "as a light automobile", limiting its market to aerial surveillance cameras for the United States Army Air Corps.[10] A later patent by Wilbur B. Rayton, assigned to Bausch & Lomb in 1943, separated one of the outer positive meniscus lenses into two air-spaced positive menisci,[11] similar to an earlier patent issued in 1938 to Hasselkus & Richmond.[12]

Although the main market for the Topogon similarly was aerial photography and mapping for military and government applications, a consumer version was produced for the pre-war Zeiss Ikon Contax 35mm rangefinder cameras and produced in small numbers as the Topogon 2.5 cm f/4. Lenses using similar designs also were produced by Canon (25mm f/3.5, 1956),[13][14] KMZ (Oриoн-15/Orion-15 28mm f/6, 1964),[15] and Nikon (W-NIKKOR·C 2.5cm f/4, 1954)[16] for their rangefinder systems after World War II.[5] In addition, Mamiya released a lens with a similar design for the Mamiya Press camera system, the Mamiya–Sekor 65mm f/6.3.[5][17][18]

Hybrid designs

The front meniscus elements of the Topogon were paired with the rear half of a double Gauss by Albrecht Tronnier and released as the Voigtlander Ultragon, a wide angle lens for large format cameras.[19]: 16–17 

As the opposite hybrid asymmetric design, the rear meniscus elements of the Topogon, forming a Gauss lens, have been paired with the front elements from a Planar-type double Gauss lens, resulting in the designs shared by the Schneider Kreuznach Xenotar (1952)[20][21] and Zeiss Planar (1953)[22] & Biometar (1959).[23] The Xenotar and Planar were fitted to Rolleiflex TLR cameras as an upgrade over Tessar/Xenar types,[24] and the Biometar was the standard lens for the Pentacon Six (aka Praktisix / Exakta 66) SLRs, with a Xenotar available for the same camera.[25]

  • Topogon derivatives
  • Topogon derivative by Hasselkus & Richmond (1936), from US 2,116,264
    Topogon derivative by Hasselkus & Richmond (1936), from US 2,116,264[12]
  • Bausch & Lomb Metrogon by Rayton (1942), from US 2,325,275
    Bausch & Lomb Metrogon by Rayton (1942), from US 2,325,275[11]
  • Voigtländer Ultragon by Tronnier (1951), from US 2,670,659
    Voigtländer Ultragon by Tronnier (1951), from US 2,670,659[26]
  • Schneider Xenotar by Klemt & Macher (1952), from US 2,683,398
    Schneider Xenotar by Klemt & Macher (1952), from US 2,683,398[20]
  • Zeiss Planar by Lange (1953), from US 2,724,994
    Zeiss Planar by Lange (1953), from US 2,724,994[22]
  • Zeiss Biometar by Zöllner (1959), from US 2,968,221
    Zeiss Biometar by Zöllner (1959), from US 2,968,221[23]

References
  1. US Patent 2031792, Robert Richter, "Anastigmatic objective for photography and projection", issued February 25, 1936, assigned to Carl Zeiss
  2. US Patent 706650, Carl Paul Goerz, "Astigmatically-corrected wide-angle objective", issued 12 August 1902, assigned to Carl Paul Goerz
  3. Richter, Robert (December 1956). "Development and Perfection of the Topogon Lens" (PDF). Photogrammetric Engineering & Remote Sensing. XXII (5): 868–874. Retrieved 9 November 2018.
  4. Kingslake, Rudolf (1989). "4. Early Double Objectives". A History of the Photographic Lens. San Diego: Academic Press. pp. 49–68. ISBN 0-12-408640-3. Retrieved 9 October 2023.
  5. 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] (in Italian). Archived from the original on December 31, 2010. Retrieved 8 November 2018.
  6. US Patent 2247068, Robert Richter, "Anastigmatic photographic objective", published June 24, 1941, assigned to Carl Zeiss
  7. DE Patent 1097710, Dr Robert Richter & Friedrich Koch, "Anastigmatisches lens", assigned to Carl Zeiss SMT GmbH
  8. Gardner, Irvine C.; Washer, Francis E. (February 1948). Lenses of Extremely Wide Angle for Airplane Mapping (Report). National Bureau of Standards, U.S. Department of Commerce. Retrieved 24 March 2023.
  9. "Zeiss Ikon". Pacific Rim Camera, Photographica Pages. Retrieved 24 March 2023.
  10. "Lens Doubles Area Covered by Aerial Camera, Saving Time in Air Corps Mapping". Popular Science. Vol. 139, no. 3. Popular Science Publishing Co., Inc. September 1941. p. 104.
  11. US Patent 2325275A, Wilbur B. Rayton, "Photographic objective", issued July 27, 1943, assigned to Bausch & Lomb Optical Company
  12. US Patent 2116264A, John William Hasselkus & George Arthur Richmond, "Objective suitable for photographic purposes", issued May 3, 1938
  13. "CANON 25mm f/3.5". Canon Camera Museum: S Lenses (19–35mm). Canon Inc. December 1956. Retrieved 26 March 2023. A super wide angle lens with a diagonal angle of view 82°, developed based on Topogon (manufactured by Carl Zeiss, Germany. Angle of view: 100°. f/6.3). This lens has a unique optical system: a spherical lens element with a very high refraction index is used as the first lens element and a special optical glass lens element with the infinite radius of curvature is used as the rearmost lens element.
  14. "Canon Rangefinder 25mm lenses". Canon Rangefinder. Retrieved 24 March 2023.
  15. "Orion-15". Soviet Cams. Retrieved 24 March 2023.
  16. Sato, Haruo. "W-NIKKOR·C 2.5cm F4 (No.29)". NIKKOR - The Thousand and One Nights. Nikon Imaging. Retrieved 24 March 2023. The entire world gradually became caught in the vortex of World War II. Under the circumstances, the Topogon lens was highly valued for its low distortion and curvature of field, and was then saddled with heavy responsibility as an optical system for aerial photography and cartography. Optical designers in many countries began to devote all their energies to develop a distortion-free, wide-angle lens of the Topogon type. In those days, the lack of an accurate map of enemy territories meant certain defeat. At that time, Nippon Kogaku was also reportedly studying vigorously the Topogon-type lenses. After peace returned to the world, the efforts of the pioneers bore fruit in the world of the artistic culture of photography. Their efforts were incorporated also in the Nikkor 2.5cm f/4.
  17. Panagopoulos, Theo (July 4, 2021). "Mamiya Press Super 23 — Frustratingly Superb". PhotoThinking. Retrieved 24 March 2023.
  18. "Mamiya Press Super 23 / Universal Press: Compact multi-format cameras, lenses, and accessories" (PDF). Pacific Rim Camera, Reference Library. Bell & Howell / Mamiya Company. February 1976. Retrieved 26 March 2023.
  19. Cröll, Arne (August 10, 2020). "Voigtländer Large Format Lenses from 1949-1972" (PDF). Retrieved 16 May 2023.
  20. US Patent 2683398, Günther Klemt & Karl Heinrich Macher, "Optical system with four air-spaced members", issued July 13, 1954
  21. Cavina, Marco. "Carl Zeiss Planar 80mm 1:2,8 per Rolleiflex TLR" [Carl Zeiss Planar 80mm 1:2,8 for Rolleiflex TLR]. NOC Sensei (in Italian). Retrieved 24 March 2023.
  22. US Patent 2724994, Günther Lange, "Photographic objective comprising four meniscus shaped air spaced components", issued November 29, 1955
  23. US Patent 2968221A, Harry Zollner, "Photographic five-element lenses of the modified Gauss type", issued January 17, 1961, assigned to VEB Carl Zeiss Jena
  24. Allen, Colton (January 25, 2018). "Rolleiflex buying guide". Film Shooter Collective. Retrieved 26 March 2023. In general though, a Planar or Xenotar should perform better than a Tessar or Xenar, especially wide open. My experience with my 2.8C Planar and 3.5F Xenotar is that the 3.5 Xenotar is a sharper lens while the 2.8 Planar has better character. I strongly suspect that has more to do with the difference of the 3.5 vs 2.8 than Planar vs Xenotar.
  25. Horton, Zach. "The Pentacon 6 Lens Hit List". Convergence. Retrieved 26 March 2023. This [Xenotar 80mm f/2.8 MF] was Schneider's entry as the best 6×6 lens in the world. It measures up. It blows away the Zeiss 80mm Planar f/2.8 made for the Hasselblad system, and that is considered the best of the best. It is sharp wide open, has mechanics to dream of (like all of the Exakta 66 lenses), and has a special character to its rendering that makes it more pleasing than any other medium format 80mm lens I've ever seen.
  26. US Patent 2670659A, Albrecht W. Tronnier, "Modified gauss-type photographic objective formed of four components arranged in two groups", published March 3, 1954, assigned to Voigtländer & Sohn AG
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