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A Short History of Fast Normal Lenses
Double Gauss, Triplet and Tessar Designs
In 1817, C. F. Gauss described a telescope objective consisting of a pair of meniscus shaped elements, one positive, and one negative. By doubling the basic Gauss lens in 1889, A. Clark was the first to describe the “Double Gauss” lens design [DOUBLEGAUSS].
In 1893, as optical manager of T. Cooke & Sons of York, makers of astronomical telescopes, H. Dennis Taylor designed a 3-element lens (“triplet”) which was able to correct all 7 Seidel aberrations [SEIDEL]: spherical aberration, coma, astigmatism, field curvature, distortion, axial chromatic and lateral chromatic aberration. In the US this design was patented in 1895 [TRIPLET].
In 1890, Paul Rudolph - while working for Zeiss - developed the "Anastigmat" with two cemented doublets. In 1899, he separated the doublets to produce the four element, four group Unar lens. In 1902, he improved the Unar's performance by joining the two rear elements into one cemented group, and named the result Tessar [TESSAR]. On first glance, the Tessar looks like an extended Cooke triplet, but it was indeed derived from a Double Gauss design.
Over the last 110 years, the basic Tessar design has been used in many designs by most camera manufacturers. From the early Leitz Elmar 50mm f/3.5, to the modern Leica M-Elmar 50mm f/2.8 and Nikkor-P 45/2.8 AIs, its simplicity, size and optical performance were at the base of many successful commercial camera designs. Tessar example pictures taken with a Leitz Elmar 5cm f/2.8 in Leica Thread Mount (LTM) can be found here.
Triplet Derivatives
The Ernostar
Based on an extension of the Cooke Triplet to four and five elements by Charles C. Minor [MINOR], in 1919, Ludwig Bertele (Ernemann Co.) replaced the front two elements of the Cooke Triplet with two cemented doublets. The first “Ernostar” was born and released as 10cm f/2 lens for use on 4,5x6cm sheet film. In 1920, Bertele improved his design to a maximum aperture of f/1.8 [ERNOSTAR].
Due to it’s compactness and performance, the above basic 5 elements in 4 group lens configuration has been used in many short tele photo lenses until today, among others the Asahi Takumars 85mm f/1.8, 85mm f/1.9, 105mm f/2.8, 120mm f/2.8, 135mm f/3.5, the Zeiss Sonnar (C/Y) 85mm f/2.8, 100mm f/3.5 and 135mm f/2.8, the Zeiss Sonnar (CG) 90mm f/2.8, and the Pentax 85mm f/2.0, 105mm f/2.8 and 120mm f/2.8.
The Sonnar
After Ernemann Co. was acquired by Zeiss-Ikon, in 1931, Ludwig Bertele completed the design of a modified Ernostar for 35mm film format, the 50mm f/2 “Sonnar” [SONNAR].
The similarity of the Sonnar to the late Ernostar is striking: the only basic modification is the replacement of the Ernostar air space between the second and third elements with an additional low dispersion glass element. With this invention, Bertele reduced the number of glass/air surfaces by two. Prior to the invention of coating in 1939 [COATING], every glass/air surface would account for an additional transmission loss of at least 5%, being reduced to less than 1% when substituted by cemented glass/glass interfaces. The name Sonnar had been used previously by Contessa. By acquiring Contessa, Zeiss also acquired rights to this name. In 1932, Bertele released an f/1.5 version with an additional cemented interface on the rear component. This allowed correction of higher-order spherical aberrations worsening with the wider lens aperture.
When German patents were opened to free use after WWII, both 50mm f/2 and 50mm f/1.5 configurations were used for Japanese and Russian Sonnar re-incarnations, among others the Canon LTM 50mm f/1.5, the Nikon rangefinder lenses 5cm f/2.0, 5cm f/1.5 and 5cm f/1.4, and the Russian Jupiter-8 and Jupiter-9 Sonnar copies. Probably the commercially most successful fast Sonnar was the Nikkor 5cm f/1.4, manufactured in both LTM and Nikon RF mount.
Example pictures taken with an LTM copy of this lens can be found here.
Double Gauss Derivatives
The Planar
In 1896, Paul Rudolph modified the basic double Gauss configuration by thickening the negative elements and reducing airspace as much as possible, for correction of spherical and sagittal/tangential astigmatic aberrations. Rudolph also inserted a "buried surface" into the thick negative elements of a cemented interface separating two types of glass having the same refractive index, but different dispersive powers. The result was the original “Planar”, a lens with 4 groups of 6 elements ([PLANAR]). During the following 40 years, this design was hardly used: light loss on the large number of glass/air surfaces caused very low contrast. However, the invention of coating ([COATING]), allowed the first commercially successful design of a Planar based lens, the Zeiss 58mm f/2 Biotar, released in 1939:
Today, most high-aperture normal lenses supplied with consumer cameras are based on this original Biotar design. The following is an incomplete list of classic normal lenses using a similar 6 elements in 4 groups configuration, where example pictures taken with the last two lenses can be found here.
The Extended Planar
Splitting the Front Doublet
The extended Planar has 6 elements in 5 groups, one cemented group behind the aperture, and the group in front has been separated (“Aufgeloester Sechs-linser”). This lens design was first calculated by A.W. Tronnier 1937 for Schneider-Kreuznach, as “Kleinbild-Xenon”. It later becoming popular as 50mm f/2 Ultron with Compur Shutter [ULTRON]:
The following is an incomplete list of classic normal lenses using a similar 6 elements in 5 groups configuration, where example pictures taken with the last two lenses can be found here.
Ultron Back Extension
The basic Ultron design was extended by adding an element to its back as first calculated by A.W. Tronnier in 1932. This design became very popular for fast 50mm lenses in the 70s. One of the most successful such design was patented by Glatzel and Behrens [EXTULTRON] and used for the Zeiss Planar 50mm f/1.4 lens, used among others for the Rolleiflex SL35 system.
The following is an incomplete list of classic normal lenses using a similar 7 elements in 5 groups configuration, where example pictures taken with the last five lenses can be found here.
Biotar Back Extension
Horace William Lee [XENON] extended the basic Planar design with an additional rear element in 1935. This same patent was used by Leitz in their first high speed normal lens in 1936, the 5cm f/1.5 Xenon (Leitz XEMOO), followed by the 5cm f/1.5 Summarit (SOOIA) in 1949 and by the Summilux 50mm f/1.4 in 1959 (SOOME), all three sharing the same basic lens configuration.
The following is an incomplete list of classic normal lenses using a similar 7 elements in 5 groups configuration, where example pictures taken with the 50mm Summilux (v2) and the Nikkor-S 55mm can be found here.
Biotar and Ultron with added Front Element
Based on Max Berek’s original Summitar design [SUMMITAR] (SOORE, a Planar with extended, cemented doublet as front element), in 1952, Ernst Leitz GmbH patented extensions to both Ultron and Biotar designs by adding an additional glass element to the front, separated by a thin “air element” [SUMMICRON]. This patent was underlying one of the most successful Leitz designs, the seven element collapsible Summicron (SOOIC).
The later “rigid” or “Dual-Range” Summicron (SOSTA) shared the same basic lens diagram with the SOOIC, albeit computer-optimized by Mandler himself. Example pictures taken with the SOSTA can be found here.
Other examples of the front-extended Biotar and Ultron designs are the Canon Rangefinder 50mm f/1.2, the 50mm f/0.95 and the Nikkor 5.8cm f/1.4, respectively. Example pictures taken with the Canon f/1.2 LTM lens can be found here.
The 35/1.4 Summilux
In the late 1950s, Mandler and Wagner extended the Biotar design with a small 7th element after the aperture to achieve the fastest wide angle lens of its time, the 35mm f/1.4 Summilux [SUMMILUX].
Leitz re-used the above basic 7 element in 5 groups configuration for the Summicron-M 35mm f/2, and the Summicron-C 40mm f/2. For photos taken with a CV 40mm f/1.4 lens with the same design, see here.
Starting with the first computer-optimized Leica lens, the Dual Range Summicron, Mandler and his team designed many classic Leica lenses until his death in 2005. Performance characteristics of some of his best know classics can be found in [MANDLER].
Summary: Genealogy
During 2013, I used 16 different 50mm lenses on film, to demonstrate characteristics of the above lens designs (click for photos). Here is how these lenses fit in their "family tree":
Online References
Below are several links that I can recommend for further study:
Paper References
Last Edited: Jul 4th, 2016 (RR)
Double Gauss, Triplet and Tessar Designs
In 1817, C. F. Gauss described a telescope objective consisting of a pair of meniscus shaped elements, one positive, and one negative. By doubling the basic Gauss lens in 1889, A. Clark was the first to describe the “Double Gauss” lens design [DOUBLEGAUSS].
In 1893, as optical manager of T. Cooke & Sons of York, makers of astronomical telescopes, H. Dennis Taylor designed a 3-element lens (“triplet”) which was able to correct all 7 Seidel aberrations [SEIDEL]: spherical aberration, coma, astigmatism, field curvature, distortion, axial chromatic and lateral chromatic aberration. In the US this design was patented in 1895 [TRIPLET].
In 1890, Paul Rudolph - while working for Zeiss - developed the "Anastigmat" with two cemented doublets. In 1899, he separated the doublets to produce the four element, four group Unar lens. In 1902, he improved the Unar's performance by joining the two rear elements into one cemented group, and named the result Tessar [TESSAR]. On first glance, the Tessar looks like an extended Cooke triplet, but it was indeed derived from a Double Gauss design.
Over the last 110 years, the basic Tessar design has been used in many designs by most camera manufacturers. From the early Leitz Elmar 50mm f/3.5, to the modern Leica M-Elmar 50mm f/2.8 and Nikkor-P 45/2.8 AIs, its simplicity, size and optical performance were at the base of many successful commercial camera designs. Tessar example pictures taken with a Leitz Elmar 5cm f/2.8 in Leica Thread Mount (LTM) can be found here.
Triplet Derivatives
The Ernostar
Based on an extension of the Cooke Triplet to four and five elements by Charles C. Minor [MINOR], in 1919, Ludwig Bertele (Ernemann Co.) replaced the front two elements of the Cooke Triplet with two cemented doublets. The first “Ernostar” was born and released as 10cm f/2 lens for use on 4,5x6cm sheet film. In 1920, Bertele improved his design to a maximum aperture of f/1.8 [ERNOSTAR].
Due to it’s compactness and performance, the above basic 5 elements in 4 group lens configuration has been used in many short tele photo lenses until today, among others the Asahi Takumars 85mm f/1.8, 85mm f/1.9, 105mm f/2.8, 120mm f/2.8, 135mm f/3.5, the Zeiss Sonnar (C/Y) 85mm f/2.8, 100mm f/3.5 and 135mm f/2.8, the Zeiss Sonnar (CG) 90mm f/2.8, and the Pentax 85mm f/2.0, 105mm f/2.8 and 120mm f/2.8.
The Sonnar
After Ernemann Co. was acquired by Zeiss-Ikon, in 1931, Ludwig Bertele completed the design of a modified Ernostar for 35mm film format, the 50mm f/2 “Sonnar” [SONNAR].
The similarity of the Sonnar to the late Ernostar is striking: the only basic modification is the replacement of the Ernostar air space between the second and third elements with an additional low dispersion glass element. With this invention, Bertele reduced the number of glass/air surfaces by two. Prior to the invention of coating in 1939 [COATING], every glass/air surface would account for an additional transmission loss of at least 5%, being reduced to less than 1% when substituted by cemented glass/glass interfaces. The name Sonnar had been used previously by Contessa. By acquiring Contessa, Zeiss also acquired rights to this name. In 1932, Bertele released an f/1.5 version with an additional cemented interface on the rear component. This allowed correction of higher-order spherical aberrations worsening with the wider lens aperture.
When German patents were opened to free use after WWII, both 50mm f/2 and 50mm f/1.5 configurations were used for Japanese and Russian Sonnar re-incarnations, among others the Canon LTM 50mm f/1.5, the Nikon rangefinder lenses 5cm f/2.0, 5cm f/1.5 and 5cm f/1.4, and the Russian Jupiter-8 and Jupiter-9 Sonnar copies. Probably the commercially most successful fast Sonnar was the Nikkor 5cm f/1.4, manufactured in both LTM and Nikon RF mount.
Example pictures taken with an LTM copy of this lens can be found here.
Double Gauss Derivatives
The Planar
In 1896, Paul Rudolph modified the basic double Gauss configuration by thickening the negative elements and reducing airspace as much as possible, for correction of spherical and sagittal/tangential astigmatic aberrations. Rudolph also inserted a "buried surface" into the thick negative elements of a cemented interface separating two types of glass having the same refractive index, but different dispersive powers. The result was the original “Planar”, a lens with 4 groups of 6 elements ([PLANAR]). During the following 40 years, this design was hardly used: light loss on the large number of glass/air surfaces caused very low contrast. However, the invention of coating ([COATING]), allowed the first commercially successful design of a Planar based lens, the Zeiss 58mm f/2 Biotar, released in 1939:
Today, most high-aperture normal lenses supplied with consumer cameras are based on this original Biotar design. The following is an incomplete list of classic normal lenses using a similar 6 elements in 4 groups configuration, where example pictures taken with the last two lenses can be found here.
- Zeiss Planar (CG) 45mm f/2
- Zeiss Planar (ZM) 50mm f/2
- Zeiss Macro-Planar (C/Y) 60mm f/2.8
- Zeiss Pancolar 50mm f/1.8
- Schneider Xenon 50mm f/2 and 50mm f/1.9
- Meyer Orestor / Pentacon 50mm f/1.8
- Helios-44 58mm/f2
- Helios-77 50mm f/1.8
- Hexanon (LTM) 50mm f/2.4 LTM
- Nikkor-H (F-mount) 50mm f/2
The Extended Planar
Splitting the Front Doublet
The extended Planar has 6 elements in 5 groups, one cemented group behind the aperture, and the group in front has been separated (“Aufgeloester Sechs-linser”). This lens design was first calculated by A.W. Tronnier 1937 for Schneider-Kreuznach, as “Kleinbild-Xenon”. It later becoming popular as 50mm f/2 Ultron with Compur Shutter [ULTRON]:
The following is an incomplete list of classic normal lenses using a similar 6 elements in 5 groups configuration, where example pictures taken with the last two lenses can be found here.
- Asahi Takumar 55mm f/1.8 and 55mm f/2.0
- Pentax 50mm f/1.7 and 55mm f/1.8
- Yashinon 50mm f/2.0 and f/1.7
- Zenitar 50mm f/1.7
- Volna-1 50mm f/1.8
- Volna-9 Macro 50mm f/2.8
- Nikkor 50mm f/1.8 AIs
- Olympus OM Zuiko 50mm f/1.8
Ultron Back Extension
The basic Ultron design was extended by adding an element to its back as first calculated by A.W. Tronnier in 1932. This design became very popular for fast 50mm lenses in the 70s. One of the most successful such design was patented by Glatzel and Behrens [EXTULTRON] and used for the Zeiss Planar 50mm f/1.4 lens, used among others for the Rolleiflex SL35 system.
The following is an incomplete list of classic normal lenses using a similar 7 elements in 5 groups configuration, where example pictures taken with the last five lenses can be found here.
- Zeiss Planar (C/Y) 50mm f/1.7
- Pentax (FA) 43mm f/1.9
- Pentax (A) 50mm f/1.2
- Canon (EF) 50mm f/1.4
- Yashica 50mm f/1.4 and 55mm f/1.2
- Porst 55mm f/1.2
- Zenitar 50mm f/1.4
- Voigtlander 50mm f/2.5 Color Skopar
- Voigtlander VM 50mm f/1.1
- Minolta AF 50mm f/1.4
- Olympus OM Zuiko 50mm f/1.4
- Olympus OM Zuiko 50mm f/1.2
- Pentax-M SMC 50mm f/1.4
- Voigtlander 50mm f/1.5 ASPH (LTM and VM)
Biotar Back Extension
Horace William Lee [XENON] extended the basic Planar design with an additional rear element in 1935. This same patent was used by Leitz in their first high speed normal lens in 1936, the 5cm f/1.5 Xenon (Leitz XEMOO), followed by the 5cm f/1.5 Summarit (SOOIA) in 1949 and by the Summilux 50mm f/1.4 in 1959 (SOOME), all three sharing the same basic lens configuration.
The following is an incomplete list of classic normal lenses using a similar 7 elements in 5 groups configuration, where example pictures taken with the 50mm Summilux (v2) and the Nikkor-S 55mm can be found here.
- Zeiss Pancolar 55mm f/1.4
- Zeiss Planar 55mm f/1.4
- Mamiya Rolleinar and Sekkor 55mm f/1.4
- Tomioka 55mm f/1.4
- Vivitar/Cosinon/Chinon/Sears 55mm f/1.4
- Canon (FL) 58mm f/1.2 and 55mm f/1.2
- Nikkor-S 55mm f/1.2
Biotar and Ultron with added Front Element
Based on Max Berek’s original Summitar design [SUMMITAR] (SOORE, a Planar with extended, cemented doublet as front element), in 1952, Ernst Leitz GmbH patented extensions to both Ultron and Biotar designs by adding an additional glass element to the front, separated by a thin “air element” [SUMMICRON]. This patent was underlying one of the most successful Leitz designs, the seven element collapsible Summicron (SOOIC).
The later “rigid” or “Dual-Range” Summicron (SOSTA) shared the same basic lens diagram with the SOOIC, albeit computer-optimized by Mandler himself. Example pictures taken with the SOSTA can be found here.
Other examples of the front-extended Biotar and Ultron designs are the Canon Rangefinder 50mm f/1.2, the 50mm f/0.95 and the Nikkor 5.8cm f/1.4, respectively. Example pictures taken with the Canon f/1.2 LTM lens can be found here.
The 35/1.4 Summilux
In the late 1950s, Mandler and Wagner extended the Biotar design with a small 7th element after the aperture to achieve the fastest wide angle lens of its time, the 35mm f/1.4 Summilux [SUMMILUX].
Leitz re-used the above basic 7 element in 5 groups configuration for the Summicron-M 35mm f/2, and the Summicron-C 40mm f/2. For photos taken with a CV 40mm f/1.4 lens with the same design, see here.
Starting with the first computer-optimized Leica lens, the Dual Range Summicron, Mandler and his team designed many classic Leica lenses until his death in 2005. Performance characteristics of some of his best know classics can be found in [MANDLER].
Summary: Genealogy
During 2013, I used 16 different 50mm lenses on film, to demonstrate characteristics of the above lens designs (click for photos). Here is how these lenses fit in their "family tree":
Online References
Below are several links that I can recommend for further study:
- Frank Mechelhoff, `History of fast 35mm and small format film lenses', 2005
- Frank Mechelhoff, `The Race for the fastest', 2006
- Wikipedia, `History of photographic lens design', 2006
- Wikipedia, `Double-Gauss lens', 2006
- Dominique Guebey, `Le triplet et sa famille', 2007
- Dominique Guebey, `Gauss et sa postérité', 2007
- Dominique Guebey, `Variantes ultra-lumineuses du type Gauss', 2007
Paper References
- [DOUBLEGAUSS] Alvan G. Clark, ‘Photographic Lens’, Patent US 399,499. (1889)
- [SEIDEL] H. D. Taylor, ‘A System of Applied Optics’. (1906)
- [TRIPLET] H. D. Taylor, ‘Lens’, Patent US 540,122. (1895)
- [TESSAR] Firma Carl Zeiss in Jena, ‘Sphärisch, chromatisch und astigmatisch korrigiertes Objectiv aus vier, durch die Blende in zwei Gruppen geteilten Linsen’, Patent DE 142,294. (1903)
- [MINOR] C. Minor, 'Photographic objective ' , Patent US 1,360,667. (1920)
- [ERNOSTAR] Ludwig Bertele, ‘Objektiv’, Patent DE 428,657. (1926)
- [SONNAR] Zeiss Ikon Aktien Gesellschaft, ‘Photographisches Objektiv’, Patent DE 570,983. (1933)
- [COATING] Firma Carl Zeiss in Jena, ‘Verfahren zur Erhoehung der Lichtdurchlaessigkeit optischer Teile durch Erniedrigung des Brechungsexponenten an den Grenzflaechen dieser optischen Teile’, Patent DE 685,767. (1939)
- [PLANAR] Firma Carl Zeiss in Jena, ‘Astigmatisch, spaerisch und chromatisch korrigiertes Objektiv’, Patent DE 92313. (1896)
- [ULTRON] Klemt Gunter, Macher Karl Heinrich, ‘Optical objective system of the Gauss type comprising five air-spaced members’, Patent US 2,683,396 (1954)
- [EXTULTRON] Karl-Heinrich Behrens and Erhard Glatzel, ‘Photographisched Objectiv vom erweiterten Gauss-Typ’, Patent DE 2,232,101. (1972).
- [XENON] Horace William Lee, ‘Lens’, Patent US 2,019,985 (1935)
- [SUMMITAR] Max Berek, ‘Photographic objective’, Patent DE 2,171,640 (1939)
- [SUMMICRON] Gustav Kleineberg and Otto Zimmermann, ‘Photographic objective lens system’, Patent US 2,622,478. (1952)
- [LAGER] James L. Lager, `Leica - An Illustrated History, Vol. 2: Lenses', ISBN-13: 978-0963697325 . (1993)
- [SUMMILUX] Walter Mandler and Erich Wagner, ‘High aperture photographic objective’, Patent US 2,975,673. (1961)
- [MANDLER] Reginald P. Jonas and Michael D. Thorpe, ‘Double Gauss lens design: a review of some classics’, Proc. SPIE 6342, International Optical Design Conference 2006, 634202. (2006)
Last Edited: Jul 4th, 2016 (RR)
