Large format lenses are photographic optics that provide an image circle large enough to cover the large format film or plates used in large format cameras.
Photographic optics generally project a circular image behind that is only required to have acceptable correction of aberrations over the intended film/sensor diagonal with little room to spare. Lenses that may be able to produce a considerably larger image circle than is needed (notably long focus lenses), but optimised for a given image format will typically mask this excess coverage off to minimize reflections and reduced contrast.
However, Some Medium and Large format cameras have movements, such as view cameras also sometimes known as technical cameras. Allowing the lens to be shifted and/or tilted from the sensor/film axis without vignetting in the corners opposite the movement requires a larger image circle. For this reason, large format lenses often produce image circles significantly larger than the film/sensor diagonal they are nominally aimed at
Compared to mainstream cameras that typically have non-interchangeable lenses and/or focal plane shutters operated from the camera body, another difference with medium and especially large format lenses is that they are typically interchangeable in a very simple manner, being mounted in a "lens board", and include a shutter just in front behind or usually in the middle of the lens. This shutter is tripped directly at the lens (possibly using a cable release), not by a release on the camera body
Note: much of the text in this section is applicable to camera lenses for all formats, not only large format lenses
Lenses of the same general construction are often given a name implying this design. For example, a Tessar always has four elements in three groups as described below, although Tessars have been produced with different focal lengths and maximum apertures for many decades. Sometimes a name does not identify a specific design; Kodak's Ektar lens brand name encompasses many different types. Sometimes different manufacturers use different names for lenses of the same type; for example, the Voigtländer Skopar is of Tessar design. And sometimes identical lenses are sold under different names and at different prices; for example, lenses branded as Rodenstock and Calder.
Early lenses suffered from flare and low contrast, worsening as the number of lens-air interfaces increased. The introduction of and improvements in anti-reflective coatings vastly reduced flare; some many-element lens designs which had been abandoned due to low contrast in spite of otherwise excellent performance became practical. Lenses designed for use with monochromatic film, first orthochromatic, then panchromatic, had less exacting requirements regarding chromatic aberrations than when colour film is used. When using older lenses today one should check those chromatic aberrations and flare are acceptable for the application.
The term wide-angle lens denotes a lens that has an image circle diameter significantly wider than the lens focal length
The term wide-angle lens denotes a lens that has an image circle diameter approximately the same as the lens focal length
The Tessar design is suitable for front-element focussing, but unit focussing is used on large format cameras.
The term long-focus lens denotes a lens that has a focal length significantly longer than the image circle diameter. For small formats such as 35mm, extreme long focus lenses can be found, with focal lengths 5, 10, or even higher multiples of the image circle, however, such extreme lenses are not normal for large formats (unless we chose to consider astronomical telescopes as cameras, which is very valid, indeed see eg Schmitt cameras and astrographs) The term telephoto has become widely if loosely used for any long-focus lens, but a true telephoto lens is designed to be physically shorter* than a simple lens of that long focal length. Typically this is achieved with a diverging group (sometimes known as the telephoto group) between the converging front group and the film/sensor. As a bonus, this rear diverging group often acts to flatten the focal plane (that would result from spherical aberrations of the front group if not corrected)
A camera lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.
A telephoto lens, in photography and cinematography, is a specific type of a long-focus lens in which the physical length of the lens is shorter than the focal length. This is achieved by incorporating a special lens group known as a telephoto group that extends the light path to create a long-focus lens in a much shorter overall design. The angle of view and other effects of long-focus lenses are the same for telephoto lenses of the same specified focal length. Long-focal-length lenses are often informally referred to as telephoto lenses although this is technically incorrect: a telephoto lens specifically incorporates the telephoto group.
Carl Zeiss AG, branded as ZEISS, is a German manufacturer of optical systems and optoelectronics, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe and Otto Schott he laid the foundation for today's multi-national company. The current company emerged from a reunification of Carl Zeiss companies in East and West Germany with a consolidation phase in the 1990s. ZEISS is active in four business segments with approximately equal revenue in almost 50 countries, has 30 production sites and around 25 development sites worldwide.
The Tessar is a photographic lens design conceived by the German physicist Paul Rudolph in 1902 while he worked at the Zeiss optical company and patented by Zeiss in Germany; the lens type is usually known as the Zeiss Tessar.
A zoom lens is a mechanical assembly of lens elements for which the focal length can be varied, as opposed to a fixed-focal-length (FFL) lens.
An apochromat, or apochromatic lens (apo), is a photographic or other lens that has better correction of chromatic and spherical aberration than the much more common achromat lenses.
A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses (dioptrics) and curved mirrors (catoptrics). Catadioptric combinations are used in focusing systems such as searchlights, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses. Other optical systems that use lenses and mirrors are also referred to as "catadioptric", such as surveillance catadioptric sensors.
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 Japanese multinational Kyocera, and featuring modern Zeiss optics. In 2005, Kyocera announced that it would no longer produce Contax cameras. The rights to the brand are currently part of Carl Zeiss AG, but no Contax cameras are currently in production, and the brand is considered dormant.
Schneider Kreuznach is the abbreviated name of the company Jos. Schneider Optische Werke GmbH, which is sometimes also simply referred to as Schneider. They are a manufacturer of industrial and photographic optics. The company was founded on 18 January 1913 by Joseph Schneider as Optische Anstalt Jos. Schneider & Co. at Bad Kreuznach in Germany. The company changed its name to Jos. Schneider & Co., Optische Werke, Kreuznach in 1922, and to the current Jos. Schneider Optische Werke GmbH in 1998.
The Zeiss Planar is a photographic lens designed by Paul Rudolph at Carl Zeiss in 1896. Rudolph's original was a six-element symmetrical design.
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 Plasmat lens is a widely used and long-established lens type invented by Paul Rudolph in 1918, especially common in large-format photography. It provides high correction of aberrations with a moderate maximum aperture. It is a specific instance of the Dagor type double-meniscus anastigmat. Double-meniscus anastigmats use widely separated positive and negative surfaces, generally thick meniscus lenses, to achieve a flat field. The most basic form is two sharply curved meniscus elements located symmetrically about a stop. Further refinement of the form replaces the two simple meniscus lenses with achromats for chromatic correction. The Dagor type further refines these achromats into triplets with the following design parameters: a high-index, doubly convex (DCX) lens cemented to a medium-index, doubly concave (DCV) lens cemented to a low-index meniscus lens. Up to this point, all refinements have maintained symmetry about the stop. The Plasmat further refines the Dagor form by uncementing the meniscus, allowing for placement away from the first two elements and removing the criterion of symmetry.
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.
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.
The Jupiter series of lenses are Russian camera lenses made by various manufacturers in the former Soviet Union. They were made to fit many camera types of the time, from pre-WWII rangefinders to almost modern SLRs. They are copied from Zeiss pre-WWII designs with incremental improvements, such as coatings, introduced during production. The majority of them are based on Zeiss Sonnar optical scheme, but that's not a rule.
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 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.
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.
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.