Metrogon

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Metrogon is a high resolution, low-distortion, extra-wide field (90 degree field of view) photographic lens design, popularized by Bausch and Lomb. Variations of this design are said to have been used extensively by the US military for use in aerial photography on the T-11 camera. [1]

Field of view extent of the observable world seen at any given moment

The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation.

Aerial photography Taking images of the ground from the air

Aerial photography is the taking of photographs from an aircraft or other flying object. Platforms for aerial photography include fixed-wing aircraft, helicopters, unmanned aerial vehicles, balloons, blimps and dirigibles, rockets, pigeons, kites, parachutes, stand-alone telescoping and vehicle-mounted poles. Mounted cameras may be triggered remotely or automatically; hand-held photographs may be taken by a photographer.

The most common Metrogon lenses have a f number of 6.3 and a focal length of 6 inches. The company name Bausch and Lomb and the US Patent number 2031792 are prominently inscribed on the front of the lens barrel. [2] However, the said US Patent is of a 4 element lens that belongs to one inventor named Robert Richter of Carl Zeiss AG, filed in 1934. [3] For this reason, it is said that the Metrogon is a US version of the popular and very similar (if not identical) Topogon design by Carl Zeiss.

The focal length of an optical system is a measure of how strongly the system converges or diverges light. For an optical system in air, it is the distance over which initially collimated (parallel) rays are brought to a focus. A system with a shorter focal length has greater optical power than one with a long focal length; that is, it bends the rays more sharply, bringing them to a focus in a shorter distance.

Patent set of exclusive rights granted by a sovereign state to an inventor or their assignee so that he has a temporary monopoly

A patent is a form of intellectual property. A patent gives its owner the right to exclude others from making, using, selling, and importing an invention for a limited period of time, usually twenty years. The patent rights are granted in exchange for an enabling public disclosure of the invention. In most countries patent rights fall under civil law and the patent holder needs to sue someone infringing the patent in order to enforce his or her rights. In some industries patents are an essential form of competitive advantage; in others they are irrelevant.

Carl Zeiss AG German manufacturer of optical systems

Carl Zeiss , branded as ZEISS, is a German manufacturer of optical systems, and industrial measurement and medical devices, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe and Otto Schott they built a base for modern optics and manufacturing. 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.

In 1943, Bausch and Lomb themselves filed a patent for a similar, f/6.3 lens design but with 5 elements, under the US patent number 2325275, showing less distortion than the lens in the Carl Zeiss patent. [4] It is not certain whether Bausch and Lomb incorporated their own design instead of the Zeiss design when producing lenses under the Metrogon name later on. The Bausch and Lomb patent also compares the distortion of their design favorably to another 5 element lens (US patent number 2116264) which has a slightly wider maximum f-number of f/5.6. [5]

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Bausch + Lomb is a Canadian eye health products company based in Laval, Quebec, Canada. It is one of the world's largest suppliers of contact lenses, lens care products, pharmaceuticals, intraocular lenses, and other eye surgery products. Founded in Rochester, New York in 1853 by optician John Bausch and financier Henry Lomb, Bausch + Lomb is one of the oldest continually operating companies in the US.

Angénieux retrofocus

The Angénieux retrofocus photographic lens is a wide-angle lens design that uses an inverted telephoto configuration. The popularity of this lens design made the name retrofocus synonymous with this type of lens. The Angénieux retrofocus for still cameras was introduced in France in 1950 by Pierre Angénieux.

Tessar trademark

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Ray-Ban company

Ray-Ban is an Italian brand of sunglasses and eyeglasses created in 1937 by the American company Bausch & Lomb. The brand is known for their Wayfarer and Aviator lines of sunglasses. In 1999, Bausch & Lomb sold the brand to the Italian eyewear conglomerate, Luxottica Group, for a reported US$640 million.

Fisheye lens

A fisheye lens is an ultra wide-angle lens that produces strong visual distortion intended to create a wide panoramic or hemispherical image. Fisheye lenses achieve extremely wide angles of view. Instead of producing images with straight lines of perspective, fisheye lenses use a special mapping, which gives images a characteristic convex non-rectilinear appearance.

Progressive lens

Progressive lenses, also called multifocal lenses, progressive addition lenses (PAL), varifocal lenses, progressive power lenses, graduated prescription lenses, or progressive spectacle lenses are corrective lenses used in eyeglasses to correct presbyopia and other disorders of accommodation. They are characterised by a gradient of increasing lens power, added to the wearer's correction for the other refractive errors. The gradient starts at the wearer's distance prescription at the top of the lens and reaches a maximum addition power, or the full reading addition, at the bottom of the lens. The length of the progressive power gradient on the lens surface depends on the design of the lens, with a final addition power between 0.75 and 3.50 dioptres. The addition value prescribed depends on the level of presbyopia of the patient. In general the older the patient, the higher the addition.

Contax Japanese camera brand

Contax began as a camera model in the Zeiss Ikon line in 1932, and later became a brand name. The early cameras were among the finest in the world, typically featuring high quality Zeiss interchangeable lenses. The final products under the Contax name were a line of 35 mm, medium format, and digital cameras engineered and manufactured by Kyocera, and featuring modern Zeiss optics. In 2005, Kyocera announced that it would no longer produce Contax cameras.

ReNu is a brand of soft contact lens care products produced by Bausch & Lomb. By far the most popular brand of lens solutions until 2006, ReNu has rebranded its formulations as renu sensitive and renu fresh, the latter containing a patented ingredient called hydranate, known by chemists as hydroxyalkylphosphonate, that removes protein deposits and can eliminate the need for a separate enzymatic cleaner.

Large format lens

Large format lenses are photographic optics that provide an image circle large enough to cover large format film or plates. Large format lenses are typically used in large format cameras and view cameras.

Double-Gauss lens

The double Gauss lens is a compound lens used mostly in camera lenses that reduces optical aberrations over a large focal plane.

Heinrich Erfle was a German optician who spent most of his career at Carl Zeiss. In 1917 he invented the first wide-field eyepieces for telescopes and binoculars. During his short life he developed a number of new designs for telescopes and eyepieces.

Zeiss Sonnar trademark

The Zeiss Sonnar is a photographic lens originally designed by Dr. Ludwig Bertele in 1929 and patented by Zeiss Ikon. It was notable for its relatively light weight, simple design and fast aperture.

The design of photographic lenses for use in still or cine cameras is intended to produce a lens that yields the most acceptable rendition of the subject being photographed within a range of constraints that include cost, weight and materials. For many other optical devices such as telescopes, microscopes and theodolites where the visual image is observed but often not recorded the design can often be significantly simpler than is the case in a camera where every image is captured on film or image sensor and can be subject to detailed scrutiny at a later stage. Photographic lenses also include those used in enlargers and projectors.

Nikkor 13mm f/5.6

The Nikkor 13mm f/5.6 is an ultra-wide angle rectilinear lens which was manufactured by Nikon for use on Nikon 135 film format SLR cameras until 1998, at which time it was discontinued. It has been dubbed 'The Holy Grail', for its low-distortion ultra-wide capabilities. The lens was produced by Nikon only upon receipt of an order, thus making it one of the Nikon lenses with the least number manufactured.

Zeiss Biogon

Biogon is the brand name of Carl Zeiss for a series of photographic camera lenses, first introduced in 1934. Biogons are typically wide-angle lenses.

Ludwig Bertele German inventor

Ludwig Jakob Bertele was a German optics constructor. His developments received universal recognition and serve as a basis for considerable part of the optical designs used today.

Topogon

Topogon is a wide field, symmetrical photographic lens designed by Robert Richter in 1933 for Zeiss Carl FA. Lenses produced under the name Metrogon also cite the US patent of the Topogon design. The initial design patented by Richter was for a f=66mm f/6.3 lens, although the patent also contains two other refinements to the basic design, including one that used parallel elements to minimize vignetting.

History of photographic lens design

The invention of the camera in the early 19th century led to an array of lens designs intended for photography. The problems of photographic lens design, creating a lens for a task that would cover a large, flat image plane, were well known even before the invention of photography due to the development of lenses to work with the focal plane of the camera obscura.

Hologon

The Zeiss Hologon is an ultra wide-angle f=15mm f/8 triplet lens, providing a 110° angle of view for 35mm format cameras. The Hologon was originally fitted to a dedicated camera, the Zeiss Ikon Contarex Hologon in the late 1960s; as sales of that camera were poor and the Zeiss Ikon company itself was going bankrupt, an additional 225 lenses were made in Leica M mount and released for sale in 1972 as the only Zeiss-branded lenses for Leica rangefinders until the ZM line was released in 2005. The Hologon name was revived in 1994 for a recomputed f=16mm f/8 lens fitted to the Contax G series of rangefinder cameras.

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