The Zeiss company was responsible for many innovations in optical design and engineering. Early on, Carl Zeiss realised that he needed a competent designer so as to take the firm beyond just being another optical workshop. In 1866, the service of Dr Ernst Abbe was enlisted. From then on novel products appeared in rapid succession which brought the Zeiss company to the forefront of optical technology.
Abbe was instrumental in the development of the famous Jena optical glass. When he was trying to eliminate astigmatism from microscopes, he realised that the range of optical glasses available was insufficient. After some calculations, he realised that performance of optical instruments would dramatically improve, if optical glasses of appropriate properties were available. His challenge to glass manufacturers was finally answered by Dr Otto Schott, who established the famous glassworks at Jena from which new types of optical glass began to appear from 1888 to be employed by Zeiss and other makers.
The new Jena optical glass also opened up the possibility of increased performance of photographic lenses. The first use of Jena glass in a photographic lens was by Voigtländer, but as the lens was an old design its performance was not greatly improved. Subsequently the new glasses would demonstrate their value in correcting astigmatism, and in the production of apochromatic lenses. Abbe started the design of a photographic lens of symmetrical design with five elements, but went no further.
Zeiss' domination of photographic lens innovation was due to Dr Paul Rudolph. In 1890, Rudolph designed an asymmetrical lens with a cemented group at each side of the diaphragm, and appropriately named "Anastigmat". This lens was made in three series: Series III, IV and V, with maximum apertures of f/7.2, f/12.5, and f/18 respectively. In 1891, Series I, II and IIIa appeared with respective maximum apertures of f/4.5, f/6.3, and f/9 and in 1893 came Series IIa of f/8 maximum aperture. These lenses are now better known by the trademark "Protar" which was first used in 1900.
At the time, single combination lenses, which occupy one side of the diaphragm only, were still popular. Rudolph designed one with three cemented elements in 1893, with the option of fitting two of them together in a lens barrel as a compound lens, but it was found to be the same as the Dagor by C.P. Goerz, designed by Emil von Hoegh. Rudolph then came up with a single combination with four cemented elements, which can be considered as having all the elements of the Protar stuck together in one piece. Marketed in 1894, it was called the Protarlinse Series VII, the most highly corrected single combination lens with maximum apertures between f/11 and f/12.5, depending on its focal length.
But the important thing about this Protarlinse is that two of these lens units can be mounted in the same lens barrel to form a compound lens of even greater performance and larger aperture, between f/6.3 and f/7.7. In this configuration it was called the Double Protar Series VIIa. An immense range of focal lengths can thus be obtained by the various combination of Protarlinse units.
Rudolph also investigated the Double-Gauss concept of a symmetrical design with thin positive meniscii enclosing negative elements. The result was the Planar Series Ia of 1896, with maximum apertures up to f/3.5, one of the fastest lenses of its time. Whilst it was very sharp, it suffered from coma which limited its popularity. However, further developments of this configuration made it the design of choice for high-speed lenses of standard coverage.
Probably inspired by the Stigmatic lenses designed by Hugh Aldis for Dallmeyer of London, Rudolph designed a new asymmetrical lens with four thin elements, the Unar Series Ib, with apertures up to f/4.5. Due to its high speed it was used extensively on hand cameras.
The most important Zeiss lens by Rudolph was the Tessar, first sold in 1902 in its Series IIb f/6.3 form. It can be said as a combination of the front half of the Unar with the rear half of the Protar. This proved to be a most valuable and flexible design, with tremendous development potential. Its maximum aperture was increased to f/4.7 in 1917, and reached f/2.7 in 1930. It is probable that every lens manufacturer has produced lenses of the Tessar configuration.
Rudolph left Zeiss after the First World War, but many other competent designers such as Merté, Wandersleb, etc. kept the firm at the leading edge of photographic lens innovations. One of the most significant designer was the ex-Ernemann man Dr Ludwig Bertele, famed for his Ernostar high-speed lens.
With the advent of the Contax by Zeiss-Ikon, the first serious challenge to the Leica in the field of professional 35 mm cameras, both Zeiss-Ikon and Carl Zeiss decided to beat the Leica in every possible way. Bertele's Sonnar series of lenses designed for the Contax were the match in every respect for the Leica for at least two decades. Other lenses for the Contax included the Biotar, Biogon, Orthometar, and various Tessars and Triotars.
The last important Zeiss innovation before the Second World War was the technique of applying anti-reflective coating to lens surfaces. A lens so treated was marked with a red "T", short for "Transparent". The technique of applying multiple layers of coating was developed from this basis after the war, and known as "T✻" (T-star).
After the partitioning of Germany, a new Carl Zeiss optical company was established in Oberkochen, while the original Zeiss firm in Jena continued to operate. At first both firms produced very similar lines of products, and extensively cooperated in product-sharing, but they drifted apart as time progressed. Jena's new direction was to concentrate on developing lenses for the 35 mm single-lens reflex camera, and many achievements were made, especially in ultra-wide angle designs. In addition to that, Oberkochen also worked on designing lenses for large format cameras, interchangeable front element lenses such as for the 35 mm single-lens reflex Contaflex, and other types of cameras.
Since the beginning of Zeiss as a photographic lens manufacturer, it has had a licensing programme which allows other manufacturers to produce its lenses. Over the years its licensees included Voigtländer, Bausch & Lomb, Ross, Koristka, Krauss, Kodak. etc. In the 1970s, the western operation of Zeiss-Ikon got together with Yashica to produce the new Contax cameras, and many of the Zeiss lenses for this camera, among others, were produced by Yashica's optical arm, Tomioka. As Yashica's owner Kyocera ended camera production in 2006, and Yashica lenses were then made by Cosina, who also manufactured most of the new Zeiss designs for the new Zeiss Ikon coupled rangefinder camera. Another licensee active today is Sony who uses the Zeiss name on lenses on its video and digital still cameras.
Wednesday, August 24, 2011
Carl Zeiss AG Lenses
Carl Zeiss AG is a German manufacturer of optical systems, industrial measurements and medical devices, founded in Jena, Germany in 1846 by Carl Zeiss, Ernst Abbe, and Otto Schott. 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.
The organisation is named after a founder, the German optician Carl Zeiss (1816–1888).
Carl Zeiss is the premier company of the Zeiss Gruppe, one of the two large divisions of the Carl-Zeiss-Stiftung. The Zeiss Gruppe is located in Heidenheim and Jena.
The other division of the Carl Zeiss Foundation, the glass manufacturer Schott AG and Jenaer Glaswerk, is located in Mainz and Jena.
Carl Zeiss is one of the oldest existing optics manufacturers in the world.
The organisation is named after a founder, the German optician Carl Zeiss (1816–1888).
Carl Zeiss is the premier company of the Zeiss Gruppe, one of the two large divisions of the Carl-Zeiss-Stiftung. The Zeiss Gruppe is located in Heidenheim and Jena.
The other division of the Carl Zeiss Foundation, the glass manufacturer Schott AG and Jenaer Glaswerk, is located in Mainz and Jena.
Carl Zeiss is one of the oldest existing optics manufacturers in the world.
Pentax Early 1950s to 2007
Early 1950s to 2007
The period around 1950 marked the return of the Japanese photographic industry to the vigorous level of the late 1930s, and its emergence as a major exporter. The newly reborn industry had sold many of its cameras to the occupation forces (with hugely more disposable income than the Japanese) and they were well received. The
Korean War saw a huge influx of journalists and photographers to the Far East, where they were impressed by lenses from companies such as Nikon and Canon for their Leica rangefinder cameras, and also by bodies by these and other companies to supplement and replace the Leica and Contax cameras they were using.
In 1952 Asahi Optical introduced its first camera, the Asahiflex (the first Japanese SLR using 35mm film). The name "Pentax" was actually created from "Pentaprism" and "Contax", this brand became a registered trademark of the East German VEB Zeiss Ikon, which later sold the name "Pentax" to Asahi Optical in 1957. Since then the company has been primarily known for its photographic products. These were imported to the United States from the 1950s until the mid 1970s by Honeywell Corporation and were labeled Honeywell Pentax rather than Asahi Pentax, the name by which they were distributed to the rest of the world. The company was renamed Pentax Corporation in 2002. It was one of the world's largest optical companies, producing still cameras, binoculars, and spectacle lenses as well as a variety of other optical instruments. In 2004 Pentax had about 6000 employees.
The period around 1950 marked the return of the Japanese photographic industry to the vigorous level of the late 1930s, and its emergence as a major exporter. The newly reborn industry had sold many of its cameras to the occupation forces (with hugely more disposable income than the Japanese) and they were well received. The
In 1952 Asahi Optical introduced its first camera, the Asahiflex (the first Japanese SLR using 35mm film). The name "Pentax" was actually created from "Pentaprism" and "Contax", this brand became a registered trademark of the East German VEB Zeiss Ikon, which later sold the name "Pentax" to Asahi Optical in 1957. Since then the company has been primarily known for its photographic products. These were imported to the United States from the 1950s until the mid 1970s by Honeywell Corporation and were labeled Honeywell Pentax rather than Asahi Pentax, the name by which they were distributed to the rest of the world. The company was renamed Pentax Corporation in 2002. It was one of the world's largest optical companies, producing still cameras, binoculars, and spectacle lenses as well as a variety of other optical instruments. In 2004 Pentax had about 6000 employees.
Pentax Camera History
The company was founded as Asahi Kogaku Goshi Kaisha in November 1919 by Kumao Kajiwara, at a shop in the Toshima suburb of Tokyo, and began producing spectacle lenses (which it still manufactures).[1] In 1938 it changed its name to Asahi Optical Co., Ltd. (旭光学工業株式会社, Asahi Kōgaku Kōgyō Kabushiki-gaisha?), and by this time it was also manufacturing camera/cine lenses. In the lead-up to World War II, Asahi Optical devoted much of its time to fulfilling military contracts for optical instruments. At the end of the war Asahi Optical was disbanded by the occupying powers, being allowed to re-form in 1948. The company resumed its pre-war activities, manufacturing binoculars and consumer camera lenses for Konishiroku and Chiyoda Kōgaku Seikō (later Konica and Minolta respectively).
Large Format Photography
What is Large Format?
This has been the contentious topic of many lengthy and futile arguments on some discussion boards. For the purpose of this article I will use the term Large Format to describe photography performed using a View Camera. View Cameras are a distinct breed with characteristics setting them apart from other camera types, such as reflex cameras (SLRs, TLRs) or rangefinder cameras.
View cameras usually have a simple construction – a front standard used to hold the lens, a rear standard used for viewing and to hold the film, a bellows connecting the two standards, and a focusing mechanism – either a monorail or a flatbed design, allowing back and forth movement of one or both standards.
Why Large Format?
Personal preferences aside, one can find advantages and disadvantages to any photographic format. View cameras offer little to no automation: the photographer performs every decision - from composition, through focusing to exposure. View Cameras require the use of a tripod and dictate a relatively slow setup and workflow process in practically every situation (some older models, like Graflex cameras, were actually designed to be used handheld by press photographers, but this mode of work will likely not work well in nature photography). View Cameras also require much longer lenses, compared to smaller formats, to cover a given angle of view. For example: a 600mm lens on a 4x5 camera will have similar coverage to a 200mm lens on a 35mm camera. These factors make the View Camera impractical for situations where the subject is very shy or likely to move at any moment (as in wildlife photography or candid images of people). The View Camera shines when the subject is static and the situation allows for a careful and calculated workflow. Here several of the format's advantages come into play:
* Large film area: View Cameras can use a variety of film types and formats – both roll film (120, 220 using a dedicated back) and sheet film (some available sizes are 2"x3", 4"x5", 5"x7", 8"x10" and even larger). The most common format is 4"x5", offering approximately 13 times the film space compared to a 35mm frame. This allows the camera to capture a tremendous amount of detail and very fine gradation in tones. These are apparent in practically any print size and more so with large prints. Photographers who have become accustomed to seeing prints from Large Format film will likely be able to pick them out in almost any side-by-side comparison.
* Control: View Cameras offer a level of control normally not found in other camera types. What sets these cameras apart is the ability to move the film plane and lens plane independently of each other, and set them at varying distances and angles relative to one another. This capability offers unparalleled control over focus and perspective. Using a View Camera you can have your plane of focus include very near and very far subjects (without having to stop down the lens), you can eliminate or intentionally create distortion resulting from tilting the lens relative to your subject etc. Consequently the View Camera can capture images that are simply not possible with other camera types that hold the lens parallel to the film at all times.
* Aspect ratio: A 4x5 frame can be printed with little to no cropping in many common standard sizes (e.g. 8x10, 16x20), allowing for more accurate framing while working in the field.
The above points make the View Camera an extremely versatile tool for landscape and architectural photography where such precise control is required, where images are often printed at large sizes, and where the photographer can take the time to apply the more elaborate workflow.
This has been the contentious topic of many lengthy and futile arguments on some discussion boards. For the purpose of this article I will use the term Large Format to describe photography performed using a View Camera. View Cameras are a distinct breed with characteristics setting them apart from other camera types, such as reflex cameras (SLRs, TLRs) or rangefinder cameras.
View cameras usually have a simple construction – a front standard used to hold the lens, a rear standard used for viewing and to hold the film, a bellows connecting the two standards, and a focusing mechanism – either a monorail or a flatbed design, allowing back and forth movement of one or both standards.
Why Large Format?
Personal preferences aside, one can find advantages and disadvantages to any photographic format. View cameras offer little to no automation: the photographer performs every decision - from composition, through focusing to exposure. View Cameras require the use of a tripod and dictate a relatively slow setup and workflow process in practically every situation (some older models, like Graflex cameras, were actually designed to be used handheld by press photographers, but this mode of work will likely not work well in nature photography). View Cameras also require much longer lenses, compared to smaller formats, to cover a given angle of view. For example: a 600mm lens on a 4x5 camera will have similar coverage to a 200mm lens on a 35mm camera. These factors make the View Camera impractical for situations where the subject is very shy or likely to move at any moment (as in wildlife photography or candid images of people). The View Camera shines when the subject is static and the situation allows for a careful and calculated workflow. Here several of the format's advantages come into play:
* Large film area: View Cameras can use a variety of film types and formats – both roll film (120, 220 using a dedicated back) and sheet film (some available sizes are 2"x3", 4"x5", 5"x7", 8"x10" and even larger). The most common format is 4"x5", offering approximately 13 times the film space compared to a 35mm frame. This allows the camera to capture a tremendous amount of detail and very fine gradation in tones. These are apparent in practically any print size and more so with large prints. Photographers who have become accustomed to seeing prints from Large Format film will likely be able to pick them out in almost any side-by-side comparison.
* Control: View Cameras offer a level of control normally not found in other camera types. What sets these cameras apart is the ability to move the film plane and lens plane independently of each other, and set them at varying distances and angles relative to one another. This capability offers unparalleled control over focus and perspective. Using a View Camera you can have your plane of focus include very near and very far subjects (without having to stop down the lens), you can eliminate or intentionally create distortion resulting from tilting the lens relative to your subject etc. Consequently the View Camera can capture images that are simply not possible with other camera types that hold the lens parallel to the film at all times.
* Aspect ratio: A 4x5 frame can be printed with little to no cropping in many common standard sizes (e.g. 8x10, 16x20), allowing for more accurate framing while working in the field.
The above points make the View Camera an extremely versatile tool for landscape and architectural photography where such precise control is required, where images are often printed at large sizes, and where the photographer can take the time to apply the more elaborate workflow.
Future of SLRs
For the foreseeable future, film-based SLRs will still be produced, as is still the case with the 35 mm film-based Nikon F6, and some other 35 mm SLR models. This is certainly true with the medium-format film-based SLRs, like the Pentax 6×7 family of cameras. Film has certain result advantages. It appears inevitable that the digital single-lens reflex camera design will eclipse film SLR's design in convenience, sales and popularity. These cameras are currently the marketing 'favorite' among advanced amateur and professional photographers
Reliability of SLRs
SLRs vary widely in their construction and typically have bodies made of plastic or magnesium. Most manufacturers don't cite durability specifications, but some report shutter life expectancies for professional models. For instance, the Canon EOS 1Ds MkII is rated for 200,000 shutter cycles and the newer Nikon D3 is rated for 300,000 with its exotic carbon fiber/kevlar shutter. Because many SLRs have interchangeable lenses, there is a tendency for dust, sand and dirt to get into the main body of the camera through the mirror box when the lens is removed, thus dirtying or even jamming the mirror movement mechanism or the shutter curtain mechanism itself. In addition, these particles can also jam or otherwise hinder the focusing feature of a lens if they enter into the focusing helicoid. The problem of sensor cleaning has been somewhat reduced in DSLRs as some cameras have a built-in sensor cleaning unit.
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