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Lens Hood
In photography, a lens hood or lens shade is a device used on the front end of a lens to block the Sun or other light source(s) to prevent glare and lens flare. Lens hoods may also be used to protect the lens from scratches and the elements without having to put on a lens cover. The geometry of a lens hood is dependent on three parameters: the focal length of the lens, the size of the front lens element and the dimensions of the image sensor or film in the camera. Cause of lens flare Flare occurs when stray light strikes the front element of a lens and then bounces around within the lens. This stray light often comes from very bright light sources, such as the Sun, bright studio lights, or a bright white background. If a light source is in the lens' angle of view, a lens hood will hardly have any effect, but the light does not have to cause lens flare. It is sufficient that stray light from a bright light source enters the lens. Multi-layer coatings in newer lenses also help to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Five Lens Hoods
5 is a number, numeral, and glyph. 5, five or number 5 may also refer to: * AD 5, the fifth year of the AD era * 5 BC, the fifth year before the AD era Literature * ''5'' (visual novel), a 2008 visual novel by Ram * ''5'' (comics), an award-winning comics anthology * ''No. 5'' (manga), a Japanese manga by Taiyō Matsumoto * The Famous Five (novel series), a series of children's adventure novels written by English author Enid Blyton Films * ''Five'' (1951 film), a post-apocalyptic film * ''Five'' (2003 film), an Iranian documentary by Abbas Kiarostami * ''Five'' (2011 film), a comedy-drama television film * ''Five'' (2016 film), a French comedy film * Number 5, the protagonist in the film ''Short Circuit'' (1986 film) Television and radio * 5 (TV channel), a television network in the Philippines (currently known as TV5 from 2008 to 2018 and again since 2020), owned by TV5 Network, Inc. * Channel 5 (British TV channel), British free-to-air television network sometime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Focus Lens
In photography, a long-focus lens is a camera lens which has a focal length that is longer than the diagonal measure of the film or sensor that receives its image. It is used to make distant objects appear magnified with magnification increasing as longer focal length lenses are used. A long-focus lens is one of three basic photographic lens types classified by relative focal length, the other two being a normal lens and a wide-angle lens. As with other types of camera lenses, the focal length is usually expressed in a millimeter value written on the lens, for example: a 500 mm lens. The most common type of long-focus lens is the telephoto lens, which incorporate a special lens group known as a ''telephoto group'' to make the physical length of the lens shorter than the focal length. Effects Long-focus lenses are best known for making distant objects appear magnified. This effect is similar to moving closer to the object, but is not the same, since perspective i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens Cover
A lens cover or lens cap provides protection from scratches and minor collisions for camera and camcorder lenses. Lens covers come standard with most cameras and lenses. Some mobile camera phones include lens covers, such as the Sony Ericsson W800, the Sony Ericsson K750 and the Sony Ericsson K550 The Sony Ericsson K550 is a mid range mobile phone. Announced on February 6, 2007, it was the successor of the K510 model sensor with two-LED photolight and an active lens cover for the camera lens protection and easy camera activation when takin .... A more secure lens cap is the metal screw-in lens cap which cannot pop off a lens accidentally. Although a screw-in cap takes more time to remove in order to take a photograph than a standard lens cap, it is stronger than plastic and therefore more protective. Some cameras (mostly compact cameras) feature an automatic lens cap that opens when the camera is powered on, they often use plastic blades and thus do not offer much protect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barn Doors
Stage lighting accessories are components manufactured for conventional (non-automated) stage lighting instruments. Most conventional fixtures are designed to accept a number of different accessories designed to assist in the modification of the output. These accessories are intended to either provide relatively common functionality not originally provided in a fixture (such as beam shaping through barn doors), or to extend the versatility of a lighting instrument by introducing features. Other accessories have been designed to overcome limitations or difficulties some fixtures present in specific applications. All stage lighting accessories fall into one of three distinct categories: components installed inside the fixture, components affixed to the front of the fixture (in front of the lens), or components mounted elsewhere on the exterior of a fixture (to the side, top or bottom). External Barn doors Barn doors, or occasionally a set of barn doors, are an attachment fitted t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellows (photography)
In photography, a bellows is the accordion-like, pleated expandable part of a camera, usually a large or medium format camera, to allow the lens to be moved with respect to the focal plane for focusing. Bellows are also used on enlarger An enlarger is a specialized transparency projector used to produce photographic prints from film or glass negatives, or from transparencies. Construction All enlargers consist of a light source, normally an incandescent light bulb shining thoug ...s. The bellows provides a flexible, dark extension between the film plane and the lens. In some cameras, the photographer can change the angle of the film plate with respect to the optical axis of the lens, providing alterations of perspective distortion and of the object plane of focus. Bellows may be part of a camera or come as an optional accessory. Types Two kinds of bellows are commonly used on cameras; bag bellows are normally used with a lens of short focal length, and accordion bellows wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF 70–200mm Lens
The EF 70–200mm lenses are a group of telephoto zoom full-frame lenses made by Canon. The lenses have an EF mount to work with the EOS line of cameras. The lens comes in seven different versions, all of which have fixed maximum aperture at all focal lengths, and are L-series lenses. * f/4L USM * f/4L IS USM * f/4L IS II USM * f/2.8L USM * f/2.8L IS USM * f/2.8L IS II USM * f/2.8L IS III USM The latest iterations of both the f/4 and the f/2.8 variants were announced on 7 June 2018. The f/4 is currently under production and the original MSRP was increased from US$1,299 to US$1,499. In March 2021, it was reported that Canon had decided to discontinue the lens. Common fields of application The f/4 USM is popular among weight-sensitive landscape photographers and hobbyists who want L lens quality without spending thousands of dollars. The f/2.8 versions are popular among event photographers and photojournalists where the lens's lower light capabilities are required. Some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentax DA 21mm Limited Lens
The Pentax smc DA 21mm F3.2 AL Limited is a moderate wide angle lens announced by Pentax on February 13, 2006. It is one of the five very compact "Limited" prime lenses for APS-C Advanced Photo System type-C (APS-C) is an image sensor format approximately equivalent in size to the Advanced Photo System film negative in its C ("Classic") format, of 25.1×16.7 mm, an aspect ratio of 3:2 and Ø 31.15 mm field d ... format cameras. Like its siblings, it was replaced in 2013 with a version that is HD-coated and has rounded aperture blades. Referenceswww.dpreview.com External links * {{Pentax K-mount lenses 21 Pancake lenses Camera lenses introduced in 2006 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF 70-300mm Lens
The EF 70–300mm lenses are a series of telephoto zoom lenses made by Canon Inc. They have a Canon EF lens mount to work with the EOS line of cameras. Four Canon EF telephoto zoom lenses carry the 70–300mm designation. *EF 70–300mm f/4.5–5.6 DO IS USM *EF 70–300mm f/4–5.6L IS USM *EF 70–300mm f/4–5.6 IS USM *EF 70–300mm f/4–5.6 IS II USM All versions offer image stabilization (IS) and ultrasonic motor drive (USM) and have nearly the same maximum aperture of 4/4.5 to 5.6 over their entire focal range. EF 70–300mm f/4.5–5.6 DO IS USM This lens makes use of Canon's Diffractive Optics rather than a traditional lens of wholly refractive design. This allows the lens to be more compact, albeit heavier and much more expensive than a lens of conventional design. The lens contains Image Stabilization and a ring USM, which allows full-time manual focusing of the lens while using the camera in single shot mode. This lens offers good optical quality with the cavea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wide-angle Lens
In photography and cinematography, a wide-angle lens refers to a lens whose focal length is substantially smaller than the focal length of a normal lens for a given film plane. This type of lens allows more of the scene to be included in the photograph, which is useful in architectural, interior and landscape photography where the photographer may not be able to move farther from the scene to photograph it. Another use is where the photographer wishes to emphasise the difference in size or distance between objects in the foreground and the background; nearby objects appear very large and objects at a moderate distance appear small and far away. This exaggeration of relative size can be used to make foreground objects more prominent and striking, while capturing expansive backgrounds. A wide angle lens is also one that projects a substantially larger image circle than would be typical for a standard design lens of the same focal length. This large image circle enables either ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Of View
The angle of view is the decisive variable for the visual perception of the size or projection of the size of an object. Angle of view and perception of size The perceived size of an object depends on the size of the image projected onto the retina. The size of the image depends on the angle of vision. A near and a far object can appear the same size if their edges produce the same angle of vision. With an optical device such as glasses or binoculars, microscope and telescope the angle of vision can be widened so that the object appears larger, which is favourable for the resolving power of the eye (see visual angle). Angle of view in photography In photography, angle of view (AOV) describes the angular extent of a given scene that is imaged by a camera. It is used interchangeably with the more general term field of view. It is important to distinguish the angle of view from the angle of coverage, which describes the angle range that a lens can image. Typically the ima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vignetting
In photography and optics, vignetting is a reduction of an image's brightness or saturation toward the periphery compared to the image center. The word '' vignette'', from the same root as ''vine'', originally referred to a decorative border in a book. Later, the word came to be used for a photographic portrait that is clear at the center and fades off toward the edges. A similar effect is visible in photographs of projected images or videos off a projection screen, resulting in a so-called "hotspot" effect. Vignetting is often an unintended and undesired effect caused by camera settings or lens limitations. However, it is sometimes deliberately introduced for creative effect, such as to draw attention to the center of the frame. A photographer may deliberately choose a lens that is known to produce vignetting to obtain the effect, or it may be introduced with the use of special filters or post-processing procedures. When using superzoom lenses, vignetting may occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
