Sonnar

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Lens sections of earlier Sonnar lenses
(1) Sonnar 1: 2 f = 5 cm ( DR 1932)
(2) Sonnar 1: 1.5 f = 5 cm (1932)
Predecessor Ernemann Anastigmat "Ernostar" 1: 1.8 f = 10.5 cm , the most advanced type (1924)
Sonnar 1: 2 f = 5 cm , Contax II ; after 1940: lens “T” coating
Sonnar 1: 1.5 f = 5 cm , Contax IIa

"Sonnar" characterized as a name or designation long and successfully produced series of photographic taking lenses , first made popular by one of Zeiss Ikon patented in 1931, and Carl Zeiss Jena made light strong 50-mm standard lens for the Contax - rangefinder camera . After the Second World War , the name “Sonnar” was used by VEB Carl Zeiss Jena in the GDR until 1990 and as a protected trademark from 1954 to 1994 by the West German legal successor Carl Zeiss- since 1947 in Oberkochen and from there mainly for marketing reasons until today - still used.

After patent protection was lost in the Second World War in 1945, Sonnar lenses were copied and modified by other manufacturers, especially in the USSR ( Jupiter , various forgeries ) and in Japan ( Zunow , Takumar , Nikkor , Serenar / Canon and others).

Due to the wide range of applications and the high optical performance of the various types, Sonnare has been sold millions of times. Well-known camera manufacturers such as Pentacon , Hasselblad , Rollei , Linhof , Sinar or Sony were or are suppliers of lenses with the name “Sonnar”.

Origin of the name "Sonnar"

Sontheim coat of arms

The idea for the naming goes back to the sun symbol in the coat of arms of the city of Sontheim am Neckar . The formerly local Nettel Camerawerk , which merged with the Contessa-Camerawerke of the designer and co-owner August Nagel in Stuttgart to form Contessa-Nettel AG in 1919 , used the name as a trademark for a relatively unknown lens similar to the Tessar in the early 1920s . Only after Contessa-Nettel was taken over by Zeiss Ikon AG in 1926 did the name "Sonnar" become known.

History and lines of development of the Sonnar lenses

The article describes in coherent sections (or largely chronologically) the lines of development of the Sonnar lens using some of the most important models, which, over a period of more than half a century, held an outstanding position among the multitude of photographic lenses.

Top lenses for the "Contax" miniature camera

From then on, the radiant sun symbol was the inspiration for the large front lens or opening of a then new type of photo lenses with spectacularly high light intensity, which Ludwig Bertele as Zeiss optics designer in the same year with the patent application by Zeiss Ikon for their Contax - the competitor product to the Leica at the time - calculated. With the standard focal length Tessar 1: 2.8 f = 5 cm Carl Zeiss Jena , the Contax was already equipped with a higher luminosity than the Leica's Leitz Elmar 1: 3.5 f = 5 cm , which was also conceived as a Tessar type , which is the case with the extremely low ones Film speeds of converted ISO 10, maximum ISO 15 meant a certain sales argument; In retrospect, however, particularly high luminous intensities were more due to the prestige than to the actual use of the then modest performance of non-dimmed, fully open lenses.

Normal focal lengths

In order to assert the quality standards against the Leitz competition, the then 26-year-old, exceptionally talented Bertele received the order to create his 1924 scheme for the trend-setting Ernemann Anastigmat " Ernostar " 1: 1.8 f = 10 for Krupp-Ernemann Kinoapparate AG , 5 cm using novel, abnormally dispersing types of glass from Jenaer Glaswerk Schott & Gen. to be further developed for the 24 × 36 mm small format of the Contax. The compact ( shortened in length ) Ernostar of the medium format camera Ernemann Ermanox was at that time the most famous brightest photo optics on the world market; The extremely innovative Ernemann lenses meant another serious competition for Zeiss that the leading optics company did not intend to tolerate: with the help of insider knowledge from Deutsche Bank and agreements with the majority owner Krupp , the company's founder Heinrich Ernemann was secretly financially infiltrated and the company was destroyed in 1926 a hostile takeover incorporated into the Zeiss group.

As a result, Bertele's 50 mm sunsets with openings 1: 2 and 1: 1.5 from 1932 consisted of 6 or 7 lenses / members in 3 groups, the cemented surfaces of which advantageously reflected less light than free-standing lenses. The implementation of this basic idea was of considerable importance, since the compensation for suppressing lens reflections while increasing the light transmission had not yet been invented. For example, an uncoated 4-lens 1: 2 Ernostar with 8 glass-air surfaces had a 48% loss of light, which reduced the effective, actually effective opening by just under −1 f-stops to 1: 2.8 (synonymous with the necessary consideration a double exposure time ).

The Carl Zeiss Jena 50 mm Sonnars that were on the market - as well as the Sonnars with medium and longer focal lengths released at the same time or a few years later - were considered superior to the photo lenses of their time, as they were at the same time brighter and more contrasting than other designs and higher resolution (see also: Sharpness ). This leadership position could be maintained for two decades until after 1945, not least through performance improvements through the T-coating used since the early 1940s and further optimizations by Bertele based on new optical glasses.

Historical feasibility study

Patent for a 50 mm Sonnar with an aperture of 1: 1.4 (1941)

The objective of improving the optical performance of the Sonnar with further increased light intensity while maintaining 6 glass-air surfaces prompted Bertele to make complex designs, which, however, were not implemented in marketable products for technical and economic reasons. US Pat. No. 2254511 A , published in 1941, shows an objective derived from the Sonnar 1: 1.5 f = 5 cm from 1932 with an aperture of 1: 1.4, the rear group of which consists of 4 cemented members in an extraordinarily complex manner. In addition to increasing the light intensity, the design also intended the indispensable reduction in coma errors when the aperture is wide open and in this way anticipated the need for at least 7, rather 8 lenses for later highly corrected ƒ / 1.2 lenses, although the Sonnar did not have them The following options were available for error correction: 5 cemented surfaces meant the waiver of the considerable number of 10 individual lens radii or exponentially increasing degrees of freedom in the optical calculation . In this respect, the design impressively demonstrates Bertele's high level of ability to use the Sonnar to create the most powerful optics among the compromise solutions offered at the time.

Medium focal lengths - the most successful suns

Sonnar - medium telephoto lens
focal lengths (35mm format)
(1) Sonnar 1: 4 f = 13.5 cm (1932)
(2) Sonnar 1: 2 f = 8.5 cm (1932)
MC Sonnar 3.5 / 135 Carl Zeiss Jena DDR for the 35mm format; later, more powerful version (production: 1980s)
Scheme of the Sonnar 1: 4/135 : Schneider-Kreuznach Tele-Xenar 1: 3.5 / 90 for the 35mm format (1957)

At about the same time as the 50 mm sunsets, in 1932 Zeiss launched a revised version of a longer focal length calculated by Bertele the year before, the success story of which - especially after 1945 in the Soviet Union and Japan - was replicated in millions, either directly or in modified form and in West Germany, models that were additionally and successfully converted to medium format - extended to the beginning of the 21st century.

The special and typical construction feature of the Sonnar 1: 4 f = 13.5 cm Carl Zeiss Jena was roughly sketched in a double link of a biconvex fluorite / fluorspar lens (fluorine crown glass ) with a high refractive index and low dispersion and an unusually voluminous, biconcave thick lens ( lead - flint glass ) with high refractive index and high dispersion, overall negative refractive power (refractive index) for image field flattening and correction of chromatic and spherical aberration while reducing the focal length . The fluorite lens had a collective function to eliminate the dispersion through chromatic undercorrection in interaction with the front converging lens , designed as a meniscus , as well as overcorrection with the thick flint glass lens. A second meniscus with positive refractive index and minimal spherical aberration corrected coma errors as the rear group and, in the opposite direction, corrected the remaining dispersion of the front groups. All in all, the methods for eliminating astigmatism and coma, as well as color errors and field curvature, resulted in excellent resolution and contrast values ​​with the aperture already open. Consisting of only 4 lenses and 6 air-glass surfaces, the 135 mm Sonnar basically embodied an independent optical construction with a shortened “telephoto” focal length.

After the Second World War, the optical structure remained unchanged and was released from around 1965 with a slightly higher light intensity. The Jena production of the 135 mm Sonnar reached a considerable number of units by the time it was phased out around 1990; Even today, both versions are among the popular lenses that are traded second-hand, even if only to an economically insignificant extent.

135 mm Ernostar / Sonnar type A. Schacht Ulm Travenar 3.5 / 135 R modernized by L. Bertele for 35mm format (production from around 1960)
Travenar 3.5 / 135

The development and production of a light intensity increased to 1: 3.5 in the form of a fundamentally revised calculation took place around 10 years earlier in Switzerland and West Germany. Emigrated to Wild Heerbrugg in Switzerland in 1946 , Ludwig Bertele had his own optics office. a. took over the lens calculations for the lens manufacturer Albert Schacht based in Ulm on the Danube . In the mid-1950s, Bertele implemented the A. Schacht Ulm Travenar 3.5 / 135 in this way, a modernization of its 135 mm Sonnar with now 4 individual lenses that can also be manufactured efficiently (for the background to these modernization measures, see also Section Recalculations under historical name ). The optical design of this telephoto lens construction combines elements of the 10 cm Ernostar and the 13.5 cm Sonnar in combination with multi-layer coatings on the lenses of high refractive / abnormally dispersing glasses and thus became a model for new developments by other manufacturers.

Comparable to the Ernostar / Sonnar type Berteles, a few years later (1964) at Carl Zeiss in Oberkochen for the Contarex and around 1975 for the post-war Contax, the light intensity of the 135 mm Sonnar in different versions was clearly set to f / 2.8 Increase, for example, to increase the correction possibilities, all 4 lenses are laid out individually or the front double element is broken down into single lenses and the meniscus of the rear group is replaced by a double element. The production of the Carl Zeiss Sonnar 2.8 / 135 T * as well as the Sonnar 2.8 / 85 T * with the Contax / Yashica bayonet , which was designed according to the same scheme, was already undergoing a turning point of technological failures, the economic negative effects of which the former the dominant position of the German camera industry in the 35mm photography sector since the end of the 1950s. At the beginning of the 1970s, Zeiss-Ikon tried to counter the stagnating camera production by cooperating with the successful Japanese manufacturer Yashica , the 35mm lens division including the newly developed optics from Carl Zeiss followed the same path after initial series production in Oberkochen.

At least according to its name, the aforementioned Sonnar 2.8 / 85 T * portrait lens has a famous ancestor in the form of the powerful Sonnar 1: 2 f = 8.5 cm Carl Zeiss Jena . It is the shortest of the telephoto lens focal lengths calculated by Bertele, which were produced in series and which all achieved a legendary reputation. After the 6-element calculation of 1933, the production of the considerably improved 7-element new calculation by L. Bertele began in 1939 in 3 groups according to the well-known lens cut. This visualizes the direct relationship with the 1.5 / 50 mm suns; In terms of relationship, this also applied to the first post-war series of the 85 mm Sonnar for the West German Contax and Contarex.

Long focal lengths - the "Olympic suns"

" Praktisix " mirror reflex camera (with Zeiss Sonnar 2.8 / 180) VEB Kamerawerke Niedersedlitz , Dresden 1956 in the German Photo Museum
Sonnar - longer telephoto lens
focal lengths (35mm format)
1) Sonnar 1: 2.8 f = 18 cm (1936, known as "Olympia Sonnar" )
2) Sonnar 1: 4 f = 30 cm (1937, "Second Olympic Sonnar " )

Following the two 135 and 85 mm Sonnars, Bertele devised an equally pioneering Zeiss lens with a longer focal length based on the lens scheme of the Sonnar 1: 2 f = 5 cm . In the 5-element telephoto lens Sonnar 1: 2.8 18 cm Carl Zeiss Jena - also known today as the "Olympia Sonnar" - a single biconvex converging lens replaces the rear 3-fold cemented element and thus illustrates the connection with the progressive Ernostar 1 : 1.8 f = 10.5 cm as the immediate predecessor of the Sonnar 1: 2 f = 5 cm . After the Second World War, Bertele's 18 cm Sonnar was recalculated - US patent 2622479 A from 1952 shows that the triple cemented element between its first and second lens was separated by a narrow air gap with different radii between the two opposing lens elements . In view of the remuneration available as standard at that time, this meant an unproblematic expansion of air-glass surfaces with the aim of better correction options. However, there is no evidence of series production of this post-war version of the "Olympia-Sonnar" from 1936 as a possible predecessor of the Carl Zeiss Sonnar 1: 2.8 f = 180 mm (4 individual lenses) built for the Contarex from 1966 onwards .

Following the extraordinary scheme of the Sonnar 1: 4 13.5 cm from 1932, Bertele calculated the Sonnar 1 in 1937 - mainly through the front second and third lens adapted to the focal length as well as by converting the rear meniscus into a correspondingly designed achromatic double link - in 1937 : 4 f = 30 cm Carl Zeiss Jena (also: "Second Olympic Sonnar"). The 5-element lens was special in that only a few specimens were produced and it was in fact a feasibility study for more extensive (presumably military) purposes, since normal use on the Contax without a special focusing device was practically impossible. After a slight revision of the 1940 invoice, it was only produced in series after the Second World War in the form of the (later remunerated) Sonnar 1: 4 f = 30 cm (T) Carl Zeiss Jena ; As by far the most expensive 35mm lens, its success in terms of numbers was low.

Further development to medium format

Scheme of the Sonnar 1: 4/135 : Carl Zeiss Sonnar 1: 5.6 f = 250 mm for the medium format (West Germany, approx. 1952)

Initially developed for the optical requirements in terms of resolution, contrast and light intensity of the 35mm format, the optical principles of Bertele's longer focal length Sonnare opened up focal length ranges up to 300 mm, whose further development in the early 1950s made use of professional medium format and view cameras up to the format 9 × 12 cm / 4 × 5 ", such as the Linhof Technika , made possible. A direct derivation of the highly esteemed Sonnar 1: 4 13.5 cm from 1932 are those made by Carl Zeiss Oberkochen from the 1950s for the world-famous and now classic 6 × 6 -Cameras manufactured by Hasselblad Carl Zeiss Sonnar T * 1: 4 f = 150 mm , 1: 4 f = 180 mm and 1: 5.6 f = 250 mm . Zeiss also manufactured these lenses to fit medium format cameras from camera manufacturers Rollei and Sinar.

For the medium format cameras Praktisix and later Pentacon Six , the Sonnar 2.8 / 180 Carl Zeiss Jena DDR came onto the market in 1959 and took over the role of its famous (35 mm) predecessor as a newly calculated medium format lens and as an adaptable 35 mm lens. In addition, the 30 cm small picture Sonnar was further developed into a medium format in 1963. The optical structure has been adopted largely unchanged; The main innovation of the Sonnar 4/300 Carl Zeiss Jena DDR is an automatic spring diaphragm which is protected by an additional flat lens. According to one source, the lens is said to have poor imaging properties that are below those of the Orestegor 4/300 Meyer-Optik Görlitz and therefore should have led to a new design. However, the lens has been tested and used several times in recent times and found to be good. According to the current state of knowledge, unacceptably high production costs in the manufacture of raw glass, especially the fluorite glasses that are laborious to melt, led to its production being stopped. After the new introduction of the so-called MC variant, at least 500 more Sonnare of the old design were manufactured, but in a black knurled frame.

"Wide-angle Sonnar" under the name "Biogon"

Biogon derived from the 50 mm Sonnar 1: 2.8 f = 3.5 cm (1936; cutaway model)

With the 50, 85, 135 and 180 mm sunsets, four elementary focal lengths of this new type of lens were available for the Contax in 1936, what was missing were matching wide-angle lenses . Their construction was particularly difficult with regard to coping with optical vignetting . Ludwig Bertele's way of solving the problem essentially consisted in dissolving the rear group of 50 mm suns and converting them to a double member and a rear lens of unusually large diameter ( exit pupil > entrance pupil ), which had an angle of view of 65 ° with only a small one Vignetting could distinguish. His calculation resulted in a test lens with the characteristic engraving pattern Sonnar 1: 2.8 f = 3.5 cm (6 lenses, 8 non-coated air-glass surfaces) and in 1936 in a revised version in the Carl Zeiss Jena Biogon 1: 2.8 f = 3.5 cm and thus marked the reference point for another extremely successful lens type.

Recalculations under historical names

modern "Sonnar" 1: 2.8 40 mm ( Rollei 35 S , small format, 1974)
Sonnar 2,8 / 40 Rollei-HFT of the Rollei 35 S (in the enlargement the arrangement of the diaphragm and shutter blades becomes visible)

The optical performance of the Sonnar was offset by a complex and expensive production, which resulted from the high requirements of the production and centering of the cemented triple links with strong curvature (long circular arcs with small radii) and the quality assurance of homogeneous, fault-free glasses, especially large-volume lenses. The remuneration of inexpensive to manufacture, narrow and less strongly curved single lenses made of metal oxide-containing optical glasses , offered by raw glass manufacturers with a large selection of different properties of high refractive index and low dispersion, allowed new developments with 3 to 4 single lenses and a maximum of one double element since the 1950s . For example, the Sonnar 2.8 / 40 Rollei-HFT for the Rollei 35 S from 1974 or the cheaper 4-lens Carl Zeiss Sonnar 2.8 / 85 for the Rollei QBM bayonet from 1970 give the impression of a return to Ludwig in the lens scheme Bertele's early 1: 2 f = 10 cm variant of the Ernostar type from 1923.

The methods mentioned above to reduce costs and the need for longer focal lengths for use on SLR (see also: retro-focus , especially at normal focal lengths and wide-angle lenses) led eventually the early 1960s to replace in particular the 50-mm-Sonnars favor of modern asymmetrical variants of the Gauss lens doublet . The new edition of the Carl Zeiss Jena Sonnar 1: 1.5 f = 5 cm from 1932 in the form of the Carl Zeiss 50 mm f / 1.5 C Sonnar T * ZM , which has been produced in small series by Cosina since mid-2000, resembles the dissolution of the triple link before the Aperture in this detail of the more modern variants of the planar lens .

In 1974 the Sonnar 4/300 MC Carl Zeiss Jena DDR with 5 lenses in 3 groups was developed in the GDR , which could also be used for the electronic aperture value transmission of the Praktica types EE2, VLC and PLC with a suitable adapter; this was essential for the Praktica EE2, otherwise the automatic timing could not be used. The design of the Sonnar 4/300 MC Carl Zeiss Jena GDR was not a Sonnar, but a teletype, "which was made up of comparatively thin lenses with large radii of curvature", and thus could be manufactured much more cheaply than the calculation for the Sonnar 4/300 Carl Zeiss Jena GDR from 1963; A reduction in optical performance, especially in the area of ​​color errors, was obviously accepted. The reason for this was probably that the cameras produced in the GDR no longer met the requirements of professional cameras, but were rather located in the field of amateur photography. The manufacturing costs had to be adjusted accordingly to ensure that the cameras and lenses continue to generate the foreign currency urgently needed for the GDR.

Nowadays, constantly further developed optics designs or construction and production methods enable complexly built, high-intensity fixed focal lengths with constantly high optical performance up to the extended close range (with a related enlarged image scale) through the combined use of optimally coated spherical or aspherical lenses and so-called floating elements . Such changed manifestations of modern lens constructions, which for some years now have also been geared towards the requirements of shorter back focal lengths of mirrorless digital cameras , ultimately led to the disappearance of practically all "classic" Sonnar focal lengths on the mass market .

Until around 2005, Carl Zeiss Oberkochen marketed a wide range of zoom lenses from its former Japanese cooperation partner Yashica (later Kyocera ) under the name Vario-Sonnar - or under this name currently with the companies Cosina and Sony - whose commonalities with Berteles Sonnaren only still exist in the famous name.

Remarks

  1. ↑ a b Lens names in italics in the article are based on the historical spelling of the respective engraving
  2. ↑ a b Zeiss T coating: “T” as in camouflage coating for optics important to the war effort, later reinterpreted as transparency or T coating , also: blue coating due to the bluish light reflections of the single-layer coatings; Hard coating made of magnesium fluoride for the outer surfaces of the front (and partially rear) lenses, cryolite for lens coatings within the lens
  3. ↑ Earlier objective lenses could only be manufactured by a combination of rotation and wobble loops , the result is always the spherical curvature of a spherical segment ; an overview of the shapes and properties of the lenses mentioned in the main text:
    • biconvex (double-convex) converging lens : positive refractive power, focusing, converging properties, outwardly curved lens radii on both sides, pronounced spherical aberration;
    • biconcave (double-concave) diverging lens : negative refractive power, diverging, scattering properties, inwardly curved lens radii on both sides, for spherical correction and shortening of focal lengths of converging lenses;
    • The designs of biconvex and biconcave lenses can be both symmetrical (both radii identical) and asymmetrical (different radii);
    • If one of the two surfaces has the radius 0, the result is plano-convex converging lenses or plano-concave diverging lenses, the production of which by flat grinding causes less costs;
    • Convex-concave meniscus lens : a) negative refractive power, diverging, scattering properties, the convex radius is larger than the concave radius, b) positive refractive power, focusing, collecting properties, the concave radius is larger than the convex radius ("half moon “), Specific properties are minimal spherical and coma errors, especially: best form lens , in: Optics - Technical Tips - lasercomponents.com, PDF, calculation diagram - optowiki.info
  4. ↑ Methods for shortening the overall length (shifting the image-side main plane of the lens to the front) were mostly used in the rear group in telephoto lenses of later designs
  5. ↑ Shorter back focal lengths, especially in combination with digital camera image sensors, require a lens design with as little natural edge light drop as possible

Individual evidence

  1. ↑ a b uncoated Sonnar 1: 2 f = 5 cm Carl Zeiss Jena - directupload.net (source) ;
    Photographic Objective US 1998704 A - depatisnet.dpma.de, patents and utility models, PDF *;
    Example of a changed optical setup (unknown date) - directupload.net (source)
  2. ↑ a b c Photographic Objective US 1975678 A - directupload.net (source) *
  3. ↑ a b Ernostar 1: 1.8 10.5 cm - directupload.net (source: fotomutori.com);
    Photographic objective US 1708863 A - depatisnet.dpma.de, PDF *;
    History of photographic lens design
  4. ↑ in: 20 years of reunification at Carl Zeiss - www.zeiss.de, PDF
  5. ↑ Sonnar word mark , registration number 675836 - register.dpma.de
  6. ↑ Jupiter 1.5 / 50 mm, 2/50 mm, 2/85 mm, 4/135 mm , in: The M39 / LTM lenses for the Zorki cameras - g-st.ch
  7. ↑ Zeiss Sonnar Fakes - klassik-cameras.de
  8. ↑ Zunow 1: 1.1 f = 5 cm - cameraquest.com
  9. ↑ in: Early Pentax Takumar Lenses - Klassik-cameras.de, in the section: Early standard lenses, Takumar 1: 2 f = 58 mm
  10. ↑ a b Rangefinder Camera Collection - klassik-cameras.de
  11. ↑ Nettel Camera work - camerapedia.wikia.com
  12. ↑ Contessa-Nettel AG - camerapedia.wikia.com
  13. ^ Contax I ; Contax II / III - cameraquest.com
  14. ↑ Zeiss Ikon Contax, Carl Zeiss Jena Tessar 1: 2.8 f = 5 cm - directupload.net, ditto Contax I.
  15. ↑ Elmar f = 5 cm 1: 3.5 - www.l-camera-forum.com
  16. ↑ Anomalous dispersion: at wavelengths of blue light reduced refractive power ;
    Refractive index and dispersion of optical lenses - laborpraxis.vogel.de
  17. ↑ a b c d Ernemann Ermanox 4.5 x 6 cm with 1: 2 f = 10 cm Ernostar lens - kameramuseum.de;
    Lens patent: Reichspatentamt patent specification No. 458 499 (July 22, 1924) - depatisnet.dpma.de, PDF *
  18. ↑ in: Andre Beyermann, The structure of Zeiss Ikon AG , Zeiss Ikon AG Dresden: Aspects of the development of the industrial enterprise founded in 1926 / Technical University of Dresden - portal.dnb.de/ German National Library
  19. ↑ a b in: Early bright lenses for 35mm and other small picture formats - klassik-cameras.de
  20. ↑ Zeiss Tipo Sonnar - marcocavina.com, lens schemes, documentation of the development from the Ernostar to the Sonnar
  21. ↑ a b To reduce reflections from camera lenses ( Memento of the original from July 8, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. - lenspire.zeiss.com, PDF; Technology and applications of optical layers - edmundoptics.de, PDF @1@ 2Template: Webachiv / IABot / lenspire.zeiss.com
  22. ↑ Ludwig Bertele's various further developments of the 50 mm sunsets before and after the Second World War (examples):
    Lens system US 2186621 A ,
    Photographic objective US 2188523 A ,
    Objective comprising three lens members axially air separated from each other in optical alignment - US 2661660 A ,
    High-aperture and high-transmission three component objective US 2600610 A ,
    Optical Objective Comprising Six-Lenses Grouped Into Three Air Spaced Components US 2663221 A ,
    Six-Lens Objective Consisting Of Three Members Air Spaced Apart US 2676516 A ,
    Three-Component Photographic Objective Formed Of Six-Lens Elements US 2687064 A - depatisnet.dpma.de, PDF *
  23. ↑ a b Photographic objective US 2254511 A - depatisnet.dpma.de, PDF *
  24. ↑ The race for the brightest lenses - klassik-cameras.de
  25. ↑ Geometric optics - wmi.badw.de, PDF
  26. ↑ a b Sonnar 1: 4 f = 13.5 cm Carl Zeiss Jena : lens or frame cut , ditto - directupload.net
  27. ↑ a b Sonnar 1: 2 f = 8.5 cm Carl Zeiss Jena (6 lenses; Jena, 1932),
    Carl Zeiss Sonnar 1: 1.5 50 mm (7 lenses; Oberkochen, approx. 1950),
    Carl Zeiss Sonnar 1 : 2 85 mm (7 lenses; Oberkochen, approx. 1951): lens scheme comparison - directupload.net;
    Carl Zeiss Jena Sonnar 1: 2 f = 8.5 cm short telephoto lens ,
    Zeiss-Opton Sonnar 1: 2.0 f = 8.5 cm short telephoto lens for Contax ,
    Zeiss Ikon Sonnar 85 mm f / 2.0 for Contarex short telephoto lens - mir.com
  28. ↑ a b MC Sonnar 3.5 / 135 Carl Zeiss Jena GDR : lens or frame cut - directupload.net
  29. ↑ Sonnar 1: 4 f = 13.5 cm Carl Zeiss Jena ;
    Sonnar 4 / 13.5: 1st bill 10/31, 2nd Re. 1/37, production from 3/32 , in: Hartmut Thiele, "Fabrication Book Photooptics II Carl Zeiss Jena" - private printing Munich 2015, 7th edition
  30. ↑ Objective classes - qualities: fluorite objectives - univie.ac.at
  31. ↑ Optical lenses - image construction and calculations - scandig.info
  32. ↑ Lens defect: Koma - univie.ac.at
  33. ↑ Lens defects: chromatic aberration - univie.ac.at
  34. ↑ Lens error: field curvature - univie.ac.at
  35. ↑ a b c Ludwig Bertele's modernized lens variants:
    A. Schacht - 35, 135 (Ernostar / Sonnar) and 85 mm (Sonnar) lenses (source) ( Memento of the original from September 28, 2016 in the Internet Archive )     Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , A. Schacht Ulm R Travenar 1: 3.5 / 135 - whitemetal.com @1@ 2Template: Webachiv / IABot / olypedia.de
  36. ↑ in the section: The Bertele era in Heerbrugg - sps.ch, Swiss Physical Society , article, September 2011
  37. ^ Lenses from A. Schacht… - photobutmore.de
  38. ↑ Carl Zeiss Sonnar T * 2.8 / 135 mm - zeiss.de, PDF
  39. ↑ a b Sonnar 85 mm f / 2.8 (4 lenses) - klassik-cameras.de or Sonnar T * 2.8 / 85 (5 lenses) - zeiss.de, PDF
  40. ↑ West German 35mm cameras - how they lost against the Japanese - klassik-cameras.de;
    The lost war - mansfeldt.net
  41. ↑ "The Sonnar 2 / 8.5 was manufactured until July 1st, 1938 with the invoice from April 24th, 1933, the Zeiss Ikon documents are unfortunately lost. From February 8th, 1939 with a new invoice with 7 lenses in 3 parts from January 16th, 1939. 1939, all invoices from Zeiss Ikon Dresden, Bertele --- from 3/3/1948 new invoice from 13/5/1947 from Carl Zeiss Jena. The new glasses created from 1943 made a revision of all optical invoices necessary, but they are not externally recognizable " Information from Carl Zeiss AG (Jena) company archive / Dr. W. Wimmer / Fr. Marte Schwabe / Hartmut Thiele October 14, 2019 / October 17, 2019
  42. ↑ a b Sonnar "Olympia" 180 mm f / 2.8 - o_tripeiro.blogs.sapo.pt;
    Contax Carl Zeiss Jena 1: 2.8 f = 18 cm Olympia Sonnar - mir.com;
    Legendary Zeiss 180 / 2.8 Olympia Sonnar - cameraquest.com;
    Sonnar 18cm f: 2.8, first direct mount, then in Flektoskop mount - camera-wiki.org - the long focal length could first be used directly on the Contax, to improve the focusing accuracy later via the Flektoskop mirror     box extension
  43. ↑ a b Copy of a (somewhat preserved) design note by L. Bertele about the Sonnar 1: 4 f = 30 cm (April 21, 1937) - directupload.net (source)
  44. ↑ a b c Sonnar 2,8 / 180 Carl Zeiss Jena DDR and Sonnar or MC Sonnar 4/300, in: Zeiss lenses with Praktisix connection - pentaconsix.com, PDF
  45. ^ Three-Component Objective - depatisnet.dpma.de
  46. ↑ Carl Zeiss Sonnar 1: 2.8 f = 180 mm - directupload.net (source)
  47. ↑ Picture of a Carl Zeiss Sonnar 1: 4 f = 30 cm T , T-coating from 1949, available for the Praktina 35mm camera ( Das Praktina-System - dresdner-kameras.de) as well as the mirror box flexometer ( Sonnar 300mm f: 4, first in Flektoskop mount, then Flektometer mount - camera-wiki.org) - the long focal length could only be focused with the mirror box extension on the (rangefinder) Contax
  48. ↑ a b Medium format lenses for Hasselblad 6 × 6 cameras: Sonnar T * 1: 5.6 f = 250 mm (lens section) - directupload.net (source) ;
    Sonnar T * f / 4 150 mm , Sonnar T * f / 4 180 mm , Sonnar T * f / 5.6 250 mm ( Memento of the original from December 6, 2015 in the Internet Archive )     Info: The archive link was inserted automatically and still Not checked. Please check the original and archive link according to the instructions and then remove this notice. - hasselbladhistorical.eu, PDF; Zeiss Sonnar 150mm f / 4 , Zeiss Sonnar 250mm f / 5.6 - kenrockwell.com @1@ 2Template: Webachiv / IABot / www.zeiss.com
  49. ↑ Carl Zeiss Sonnar 1: 4.8 f = 180 mm Linhof Technika - directupload.net (source: Flickr) , ditto - directupload.net, Netzfund
  50. ↑ Sonnar lenses for Rollei and Sinar medium format cameras - zeiss.de
  51. ↑ Sonnar 2,8 / 180 Carl Zeiss Jena GDR ("Zebra" frame), lens or frame cut - directupload.net;
    Carl Zeiss Jena DDR Sonnar 2.8 / 180 - lensbeam.com
  52. ↑ Lens tests with a special camera - zeissikonveb.de; the (not verified) comparison shows a comparatively high imaging performance of the Sonnar 4/300 Carl Zeiss Jena DDR ("Zebra" version)
  53. ↑ Astrotreff - Astronomy meeting point - M31 with Sonnar 4/300. Retrieved January 24, 2020 .
  54. ↑ Carl Zeiss Jena 4/300 (Pentacon Six, P6), black version, NO MC. Retrieved January 24, 2020 .
  55. ↑ MC Sonnar 4/300
  56. ↑ a b Carl Zeiss Jena wideangle lens Biogon 1: 2.8 f = 35 mm , ditto - mir.com;
    Frame and lens cut - directupload.net, Netzfund
  57. ↑ Sample Sonnar 1: 2.8 f = 3.5 cm - directupload.net (source)
  58. ↑ patent filing from January 6, 1936 (Ludwig Bertele, Zeiss Ikon AG) for a 7-lens wide-angle lens: Photographic lens system US 2,084,309 A - directupload.net (source) *;
    Due to missing construction plans, there are different, sometimes contradicting information in the literature about the optical structure of the 3.5 cm Biogon implemented in series production (compare Biogon 1: 2.8 f = 3.5 cm , illustration from the Zeiss Ikon Main catalog 1938 (source) ; Cavina ; Gubas ; Merté, Richter, v. Rohr: Handbook of scientific and applied photography ; Zeiss Ikon Dresden: Contaxphotographie - Zeiss Ikon 35mm cameras , brochures C 740 b / c, late 1930s)
  59. ↑ Centering: minimization of tilting as well as radial and axial displacement of the central axis of individual lenses in optical systems; Decentration - Spektrum.de
  60. ↑ Optical Glass , PDF, Optical Glass - schott.com;
    Optical glass - edmundoptics.de
  61. ↑ Rollei QBM mount lens program - klassik-cameras.de
  62. ↑ Zeiss 50 mm f / 1.5 Sonnar T * ZM - kenrockwell.com
  63. ↑ Is it a real Sonnar? - Klassik-cameras.de
  64. ↑ Sonnar 300 mm f / 4 MC - o_tripeiro.blogs.sapo.pt;
    Lenses for the Pentacon Six - dresdner-kameras.de;
    the Sonnar 4/300 MC Carl Zeiss Jena could be connected for the M42 lens connection and the miniature camera Kine Exakta using an adapter with a spring     shutter function
  65. ↑ Sonnar 4 / 300mm - zeissikonveb.de; the article shows the lens schemes in comparison
  66. ↑ Lens tests with a special camera - zeissikonveb.de; the (not verified) comparison shows that the Sonnar 4/300 MC Carl Zeiss Jena DDR has a poorer imaging performance than the earlier zebra version without MC
  67. ↑ Examples of modern "Sonnar" fixed focal lengths:
    Carl Zeiss Apo Sonnar 2/135     mm ZE T * - directupload.net (source) , technical specifications ( memento of the original from September 29, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. - zeiss.com, PDF, Zeiss / Sony Sonnar T * 135 mm F1.8 ZA - directupload.net (source) , Zeiss / Sony Sonnar T * FE 55 mm F1.8 ZA - directupload.net (source) , ditto - kenrockwell.com @1@ 2Template: Webachiv / IABot / www.zeiss.com

  68. ↑ Vario-Sonnar f / 4 80 - 200 mm ( Memento of the original from November 23, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , f / 3.5 70 - 210 mm , f / 3.5 40 - 80 mm ( Memento of the original from April 12, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , f / 3.5 - 4.5 24 - 85 mm , f / 3.3 - 4.0 28 - 85 mm ( Memento of the original from April 12, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , f / 4.5 45 - 90 mm , f / 3.5 - 4.5 28 - 70 mm , f / 3.5 - 5.6 35 - 70 mm , f / 2.8 17 - 35 mm , f / 3.3 - 4.5 35 - 135 mm - zeiss.de , zeiss.com, PDF @1@ 2Template: Webachiv / IABot / www.zeiss.com @1@ 2Template: Webachiv / IABot / www.zeiss.com @1@ 2Template: Webachiv / IABot / www.zeiss.com
  69. ↑ Carl Zeiss quality made by Cosina - zeiss.com, May 2007, PDF
  70. ↑ Sony and Zeiss… - blogs.zeiss.com

See also

Web links