Tessar
|
| original Tessar from Zeiss collection image by Uwe Kulick (Image rights) |
The Tessar is a camera and projection lens designed by Paul Rudolph, working for the Carl Zeiss Jena company, in 1902. It is normally used as a standard lens, and versions of it have been fitted to many millions of cameras.
The design consists of four elements in three groups; the front element is positive, bi-convex (with the rear almost flat), the central a negative bi-concave and, following an aperture, at the rear is a cemented doublet of plano-concave and a bi-convex elements. Though often referred to as a "modified Cooke triplet", the Tessar is actually a development of Rudolph's 1899 Unar (4 element in 4 groups) lens, itself a development of Rudolph's 1890 Zeiss Anastigmat (4 elements in 2 groups) lens.[1]
|
| Cross-section of a 50mm f2.8 Tessar, with front element on the left. (for 35mm, M42 fitting) by AWCam (Image rights) |
|
| Cut-away diagram of a Tessar scanned by Uwe Kulick (Image rights) |
The first patented design is for an f/5.5 lens.[2] This design was not made commercially, however; the first Tessars offered for sale were an f/6.3, and an f/10 apochromatic lens (that is, one corrected to give the same focus at three wavelengths);[3] developments in design allowed f/2.8 by 1930.
In addition to production by Carl Zeiss, the Tessar name and design (under license) was used in the production of numerous lenses by Bausch & Lomb (Rochester), Ross (London) and Krauss (Paris).
The Tessar design has been widely copied by nearly all major optics companies. By 2002, Carl Zeiss, Inc. had produced over five million Tessar lenses, and they estimated the total number of Tessar formula lenses at more than 150 million.[4]
A very partial list includes:
- Agfa Solinar
- Asahi/Pentax Macro-Takumar 50mm f/4
- Bausch & Lomb Tessar (under license)
- Canon 50mm FL f/3.5, 38mm FLP, 50mm f/2.8 and f/3.5(RF), 35mm f/3.5(RF)
- Dallmeyer Dalmac, Perfac, Serrac
- Ernemann Ernon
|
| Tessar Series 1c Pat Feb 24, 1903 made by Bausch & Lomb image by Nesster (Image rights) |
- FED/KMZ Industar
- Ilex Paragon
- Kodak Ektar
- Konica Macro-Hexanon AR 55 mm f/3.5
- Krauss-Zeiss Tessar (under license)
- Leitz Elmar
- Mamiya Press lenses - 100mm f/3.5, 127mm f/4.7, 150mm f/5.6
- Meyer Primotar
- Minolta Rokkor TLR
- Minox Minoxar
- Nikon 45mm GN Nikkor, El-Nikkor 50mm f/4
- Olympus in many of their compact cameras including the Trip 35 (40mm f/2.8) and mju series.
- Plaubel Anticomar
- Rodenstock Ysar, Rogonar
- Ross Xtralux
|
| Tessar on Ikonta image by Mario Groleau (Image rights) |
- Ross Tessar (under license)
- Schneider Xenar, Comparon
- Taylor & Hobson Apotal, Ental
- Voigtlander Heliostigmat, Skopar
- Wollensak Raptar
- Yashica Yashinon TLR, Yashica T AF
- Zeiss Tessar
Notes
- ↑ Kingslake, Rudolph, A History of the Photographic Lens, Academic Press, (1989). "It is certain that the Tessar was not a modified Cooke Triplet, as the series of steps followed by Dr. Paul Rudolph in going from the Anastigmat to the Tessar are well established, but for some of the later designs it is not always clear whether they should be regarded as modified Tessars or modified Triplets." Nevertheless, the easiest way of describing a Tessar is to explain how it differs from a simple triplet, and this is what is meant by those who call it a modified triplet, rather than implying any particular design process.
- ↑ Austrian Patent 13124, Sphärisch, chromatisch und astigmatisch korrigiertes Objektiv (spherically-, chromatically- and astigmatically-corrected lens), filed June 1902 and granted March 1903 to the Karl (sic) Zeiss company of Jena; US Patent 721240, Photographic Objective, filed July 1902 and granted February 1903 to Paul Rudolph and the Carl Zeiss company; both describing an f/5.5 Tessar design; at Espacenet, the patent search facility of the European Patent Office.
- ↑ Greenleaf, Allen R. (1950) Photographic Optics, Macmillan, New York, p77-82.
- ↑ Innovation – The Magazine from Carl Zeiss", Issue 11, Carl Zeiss, Inc.
