Fisheye 15 mm (type: equisolid angle), 35 mm-film, cropped by slide-frame. Complete room (4 walls, ceiling and floor).

In photography, a fisheye lens is a wide-angle lens that takes in an extremely wide, hemispherical image. Photography (fә'tɒgrәfi or fә'tɑːgrәfi (from Greek φωτο and γραφία is the process and Art of recording pictures by means of capturing "Globose" redirects here See also Globose nucleus. A sphere (from Greek σφαίρα - sphaira, "globe Originally developed for use in meteorology and astronomy and called "whole-sky lenses", fisheye lenses quickly became popular in general photography for their unique, distorted appearance. Meteorology (from Greek grc μετέωρος metéōros, "high in the sky" and grc -λογία -logia) is the Interdisciplinary Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study They are often used by photographers shooting broad landscapes to suggest the curve of the Earth. Hemispherical photography is used for various scientific purposes to study plant canopy geometry and to calculate near-ground solar radiation. Hemispherical photography, also known as fisheye or canopy photography is a technique to estimate Solar radiation and characterize plant canopy geometry

The focal lengths of fisheye lenses depend on the film format. The focal length of an optical system is a measure of how strongly it converges (focuses or diverges (diffuses Light. A film format is a technical definition of a set of standard characteristics regarding image capture on Photographic film, for either stills or movies For the popular 35 mm film format, typical focal lengths of fisheye lenses are between 8 mm and 10 mm for circular lenses, and 15-16 mm for full-frame lenses.

All the ultra-wide angle lenses suffer from some amount of barrel distortion. While this can easily be corrected for moderately wide angles of view, rectilinear ultra-wide angle lenses with angles of view greater than 90 degrees are difficult to design. In Photography, angle of view describes the angular extent of a given scene that is imaged by a Camera. In Photography, a rectilinear lens is a Photographic lens that yields images where straight features such as the walls of buildings appear with straight lines as Fisheye lenses achieve extremely wide angles of view by foregoing a rectilinear image, opting instead for a special mapping (for example: equisolid angle), which gives images a characteristic convex appearance. A panorama by rotating lens or stitching images (cylindrical perspective) is not a fisheye photo. In its most general sense a panorama is any wide view of a physical space Cylindrical perspective is caused by fisheye and Panoramic lenses which reproduce straight horizontal lines above and below the Lens axis level as curved

Types of fisheye lenses

In a circular fisheye lens, the image circle is inscribed in the film or sensor area; in a full-frame fisheye lens the image circle is circumscribed around the film or sensor area. In Geometry, an inscribed Planar Shape or solid is one that is enclosed by and "fits snugly" inside another geometric shape or solid

Further, different fisheye lenses distort images differently, and the manner of distortion is referred to as their mapping function. A common type for consumer use is equisolid angle.

Circular

The picture using a circular fish eye lens

The first types of fisheye lenses to be developed were "circular fisheyes" — lenses which took in a 180° hemisphere and projected this as a circle within the film frame. Some circular fisheyes were available in orthographic projection models for scientific applications. Orthographic projection is a Map projection of Cartography. Like the Stereographic projection and Gnomonic projection, Orthographic

These have a 180° vertical angle of view, and the horizontal and diagonal angle of view are also 180°. In Photography, angle of view describes the angular extent of a given scene that is imaged by a Camera.

Full-frame

Fisheye 10. 5 mm Nikkor (type: equisolid angle), APS-C sized sensor, cropped to rectangle. Nikkor is the brand of lenses produced by Nikon Corporation, including camera lenses for the Nikon F-mount.

As fisheye lenses gained popularity in general photography, camera companies began manufacturing fisheye lenses that enlarged the image circle to cover the entire 35 mm film frame, and this is the type of fisheye most commonly used by photographers.

The picture angle produced by these lenses only measures 180 degrees when measured from corner to corner: these have a 180° diagonal angle of view, while the horizontal and vertical angles of view will be smaller; for an equisolid angle-type 15 mm full-frame fisheye, the horizontal FOV will be 147°, and the vertical FOV will be 94°. In Photography, angle of view describes the angular extent of a given scene that is imaged by a Camera. ^[1]

The first full-frame fisheye lens to be mass-produced was a 16 mm lens made by Nikon in the late 1960s. ( also known as Nikon or Nikon Corp, is a Multinational corporation headquartered in Tokyo Japan specializing in Optics The 1960s decade refers to the years from the beginning of 1960 to the end of 1969 Digital cameras with APS-C sized sensors require a 10. Advanced Photo System type-C ( APS-C) is an Image sensor format approximately equivalent in size to the Advanced Photo System "classic" size negatives 5 mm lens to get the same effect as a 16 mm lens on a camera with full-frame sensor. ^[2]

Focal length

The widest lens ever produced was a 6 mm circular fisheye made by Nikon. ( also known as Nikon or Nikon Corp, is a Multinational corporation headquartered in Tokyo Japan specializing in Optics Initially designed for an expedition to Antarctica, it featured a 220-degree field of view, designed to capture the entire sky and surrounding ground when pointed straight up. This lens is still manufactured by Nikon upon special order[1], and is used nowadays to produce interactive virtual-reality images such as QuickTime VR and IPIX. QuickTime VR ( Virtual reality) (also known as QTVR) is a type of image file format supported by Apple 's QuickTime. IPIX (IPIX Corporation was an imaging technology company headquartered in Reston Virginia. Because of its very wide field of view, it is very large and cumbersome - weighing 5. 2 kg (11. 5 lb) and having a diameter of 236 mm (9. 3 in). It dwarfs a regular 35mm SLR camera[2] and has its own tripod mounting point, a feature normally seen in large long-focus or telephoto lenses to reduce strain on the lens mount because the lens is heavier than the camera. A lens mount is an interface — mechanical and often also electrical — between a photographic Camera body and a lens

An 8mm fisheye lens, also made by Nikon, has proven useful for various scientific uses because of its equidistant (equiangular) projection, in which distance along the radius of the circular image is proportional to zenith angle. ( also known as Nikon or Nikon Corp, is a Multinational corporation headquartered in Tokyo Japan specializing in Optics In Astronomy, a celestial coordinate system is a Coordinate system for mapping positions in the sky

Other uses

• Some planetariums use a form of fisheye lens to project a two-dimensional film image of the night sky onto the interior of a dome. A planetarium is a Theatre built primarily for presenting educational and entertaining shows about Astronomy and the night sky or for training in Celestial navigation
• Similarly, the IMAX Dome (previously 'OMNIMAX') motion-picture format involves photography through a circular fisheye lens, and projection through the same onto a hemispherical screen. IMAX (short for Image MAXimum is a Film format created by Canada 's IMAX Corporation that has the capacity to display images of far greater size and
• Scientists and resource managers (e. g. , biologists, foresters, and meteorologists) use fisheye lenses for hemispherical photography to calculate plant canopy indices and near-ground solar radiation. Hemispherical photography, also known as fisheye or canopy photography is a technique to estimate Solar radiation and characterize plant canopy geometry Applications include evaluation of forest health, characterization of monarch butterfly winter roosting sites, and management of vineyards. The monarch ( Danaus plexippus) is a Milkweed butterfly ( Subfamily Danainae in the family Nymphalidae. A vineyard is a Plantation of Grape -bearing Vines grown mainly for Winemaking, but also Raisins Table grapes and non-alcoholic
• Photographers and videographers use fisheye lenses so they can get the camera as close as possible for action shots, for example in skateboarding to focus on the board and still retain an image of the skater. Skateboarding is the act of riding and performing tricks using a Skateboard.
• The peepholes used in doors contain fisheye lenses.
• Many scenes of the film A Clockwork Orange were filmed with a fisheye lens. A Clockwork Orange is a 1971 Satirical Science fiction Film adaptation of a 1962 novel of the same name, by Anthony
• The first music video to be shot completely with fisheye lens was for the Beastie Boys song "Shake Your Rump" in 1989. " Shake Your Rump " is the 2nd track on Paul's Boutique by American hip hop group the Beastie Boys, released on July 25

Fisheye lenses for 35mm cameras

Circular fisheye

• Sigma 8mm f/3.5 EX DG (replaces the Sigma 8mm f/4 EX DG. The Sigma 8mm f/35 EX DG is a Photographic lens introduced on 9 August, 2006. The Sigma 8mm f/4 EX DG is a Photographic lens made by the Sigma Corporation.
• Sigma 4. 5mm f/2. 8 EX DC Circular Fisheye HSM for APS-C sensors. Advanced Photo System type-C ( APS-C) is an Image sensor format approximately equivalent in size to the Advanced Photo System "classic" size negatives
• Canon FD 7. 5mm f/5. 6; note that this is not a EF mount, and is not in production. The EF lens mount allows all the Canon EF lenses to be used on any of the Canon EOS line of Cameras made by Canon Inc
• Peleng 8mm

Full-frame fisheye

• 15mm f/2.8 EX DG Diagonal Fisheye
• Sigma 10mm f/2. 8 EX DC Fisheye HSM for APS-C sensors. Advanced Photo System type-C ( APS-C) is an Image sensor format approximately equivalent in size to the Advanced Photo System "classic" size negatives
• Zoom Tokina 10-17mm f/3. 5-4. 5 fisheye lens for APS-C sensors

Mapping function

Original tunnel to be photographed, with camera looking from inside center to left wall.	Gnomonical	Gnomonical, 40° right pan	Linear scaled (equidistant)
Orthographic	Equal area (equisolid angle)	Stereographic (conform)

The mapping of a sideways object leads to a picture position displacement from the image center. The manner of this conversion is the mapping function. The distance of a point from the image center 'r' is dependent on the focal length of the optical system 'f', and the angle from the optical axis 'θ'.

Normal (non-fisheye) lens:

• Gnomonical or perspective: r = ftan(θ). Works like the pinhole camera. Straight lines remain straight (distortion free). "θ" has to be smaller than 90°. The aperture angle is gaged symmetrically to the optical axis and has to be smaller than 180°. Large aperture angles are difficult to design and lead to high prices.

Fisheye lenses can have many different mapping functions:

• Linear scaled (equidistant): , where θ is in radians. The radian is a unit of plane Angle, equal to 180/ π degrees, or about 57 Practical for angle measurement e. g. , star maps. PanoTools uses this type. Panorama Tools (also known as PanoTools) are a suite of programs and libraries originally written by the German Physics and Mathematics
• Orthographic: r = fsin(θ). Looks like an orb with the surroundings lying on < max. 180° aperture angle.
• Equal area (equisolid angle): r = 2fsin(θ / 2). Looks like a mirror image on a ball, best special effect (unsophisticated distances), suitable for area comparison (clouds grade determination). This type is popular but it compresses marginal objects. The prices of these lenses are high, but not extreme.
• Stereographic (conform): r = 2ftan(θ / 2). This mapping would be ideal for photographers because it doesn't compress marginal objects. Although no lens has yet been developed for this type, this mapping is easily implemented by software.

All types of fisheye lens bend straight lines. Aperture angles of 180° or more are possible only with large amounts of barrel distortion.

See also

• Map projection

References

External links

• Fisheye projection theory
• Fisheye virtual photography
• A large list of fisheye lenses