Lenses are used as prosthetics for the correction of visual impairments such as myopia, hyperopia, presbyopia, and astigmatism.

Lenses with apertures larger than 2. 8 are typically known as " fast " lenses, though this has changed historically ( in the past, larger than 6 was considered fast, for example by the 1911 Encyclopaedia Britannica ).

Lenses have now been developed with so much oxygen permeability that they are approved for overnight wear ( extended wear ).

Lenses approved for daily wear are also available in silicone hydrogel materials.

* Canon EOS Technoclopedia: Exakta AF Lenses for Canon EF-a lens chart with technical data and comments

Lenses offered for the S2 include Summarit-S in normal ( 70 mm ), wideangle ( 35 mm ), and macro ( 120 mm ) varieties, and Tele-Elmar ( 180 mm ) portrait-length telephotos ; these are available in versions that feature integrated multi-leaf blade shutters (" Central Shutter ", or CS ), in addition to the focal-plane shutter in the camera body, to enable higher flash sync speeds.

Mamiya 645 Super and its possible configurations1 – Camera body ; 2 – Lenses ; 3 – Focusing screens ; 4 – Power drive ; 5 – Wind-up crank ; 6 – Metered prism finder ; 7 – Prism finder ; 8 – Waist level finder ; 9 – 120 roll film holder loaded with a film X ; 10 – 120 roll film holder loaded with a film Y ; 11 – 220 roll film holder, 35 mm roll film holder, Polaroid land pack film holder, digital back ( only for more recent models ), etc.

Lenses have already appeared whose image quality would have been marginal or unacceptable in the film era, but are acceptable in the digital era because the cameras for which they are intended automatically correct their defects.

* Lenses for SLR and DSLR cameras

Lenses or flash units of parallel imports often only differ by the warranty provided, and since the grey sets were manufactured for another state, photographic equipment manufacturers often offer local warranty, instead of international warranty, which will render grey sets ineligible for warranty claims with the manufacturer.

* Lenses for Bronica and Plaubel Makina medium format cameras.

* Lenses for Nikon S-series ( S-mount ) and Leica rangefinder cameras

* Lenses for large format photography.

" Glare Aware Photography: 4D Ray Sampling for Reducing Glare Effects of Camera Lenses ",

Lenses for the earlier Canon FD lens mount are not usable for general photography on an EF or EF-S mount camera, unless adapters with optical elements are used because they are made for a flange focal distance of only 42. 0 mm.

The Surmet Corporation has acquired Raytheon's AlON business and is currently building a market for this technology in the area of Transparent Armor, Sensor windows, Reconnaissance windows and IR Optics such as Lenses and Domes and as an alternative to quartz and sapphire in the semiconductor market.

* Lenses for SLR and DSLR cameras

Lenses such as the Nikon PC-E and Canon TS-E series, the Hartblei Super-Rotator, the Schneider Super Angulon, several Lensbaby models, the Zoerk Multi Focus System, and various tilt-shift adapters for medium format, allow the use of tilt in cameras with fixed lens mounts.

Lenses designed specifically for APS-C sized sensors are often optically designed to provide a narrower light cone to match the sensor.

* Canon EOS Technoclopedia: Voigtländer AF / MF Lenses for Canon EF-a lens chart with technical data, comments and test references

* Canon EOS Technoclopedia: Cosina AF Lenses for Canon EF-a lens chart with technical data, comments and test references

* Canon EOS Technoclopedia: Vivitar AF / MF Lenses for Canon EF-a lens chart with technical data, comments and test references

Lenses designed for the smaller digital formats include Canon EF-S lenses, Nikon DX lenses, Olympus Four Thirds System lenses, Sigma DC lenses, Tamron Di-II lenses, Pentax DA lenses, and Sony Alpha ( SAL ) DT & E lenses.

* Canon EF Portrait Lenses

Lenses are changed faster than with a screw mount, and framelines set automatically.

Although named after Dutch astronomer Willebrord Snellius ( 1580 – 1626 ), the law was first accurately described by the Arab scientist Ibn Sahl at Baghdad court, when in 984 he used the law to derive lens shapes that focus light with no geometric aberrations in the manuscript On Burning Mirrors and Lenses ( 984 ).

Lenses did not need a great depth of field, but had to be capable both of producing a very sharp image with high resolution of a flat surface and of doing so at high speed.

Lenses with large numbers of elements such as zooms tend to exhibit greater lens flare, as they contain multiple surfaces at which unwanted internal scattering occurs.

Lenses of shorter focal length are called wide-angle lenses, while longer-focal-length lenses are referred to as long-focus lenses ( with the most common of that type being the telephoto lenses ).

Lenses with focal lengths of 8 to 16 mm may be either rectilinear or fisheye designs.

Lenses glued with Canada balsam ( or with other similar glues ) are called cemented lenses.

Lenses with desgnation " AR " were designed for the non reflex Bolex cameras.

Lenses of 55 mm focal length and shorter are 7 elements, and 60 and longer are 6, with no cemented surfaces to avoid any possible damage due to heat.

Lenses with smaller base curves are referred to as " steep ".

Lenses shorter than 50 mm are not recommended for use with a No. 486 filter due to a tendency for the corners of the image to take on a cyan color cast.

Lenses with AI capability include AI and AI-s type Nikkor lenses and Nikon Series E Lenses.

Lenses from Sankyo Kohki Komura, Zeiss Jena, and Bronica itself were available, as well as a wide range of accessories, including different film magazines, bellows, and viewfinders.

Lenses designed for use with monochromatic film, first orthochromatic, then panchromatic, had less exacting requirements regarding chromatic aberrations than when colour film is used.

* Progressive Addition Lenses, used in eyeglasses and which are characterised by a gradient of increasing lens power

Lenses made this way are sometimes used as objectives in refracting telescopes.

Lenses of identical focal lengths and maximum apertures that spanned both generations, in addition to their altered mounts, were typically smaller and lighter in the New FD generation, and usually used smaller diameter filters.