wiktionarypar lensLens or Lense may refer to TOC right Optics Lens optics , an optical element which converges or diverges light Lens anatomy , a part of the eye Corrective lens for correction of human vision Contact lens , placed on the cornea of the eye Photographic lens , a lens designed for use on a camera Focusing of other radiation and forces Gravitational lens , a massive astronomical object which causes visual distortions Electrostatic lens , a device used to focus or collimate electron beams Explosive lens , a shaped explosive charge with focused blast Microwave lens , used to focus microwave radiation in slotted waveguide antennas Lentil shaped things Lens genus , the genus of the lentil plant Lens geometry , a geometric shape formed from two arcs Lens geology , a body of ore or rock that is thick in the middle and thin at the edges Lens hydrology , a layer of fresh water derived from rainfall, overlying saline groundwater Kamera lens biology , a unicellular, flagellate organism and the only species of the genus Kamera. Places Arrondissement of Lens , in the d partement of Pas de Calais, France Lens, Pas de Calais , a commune in that arrondissement RC Lens , its football soccer club Lens, Belgium Lens, Valais , Switzerland People Louis Lens , Flemish rose breeder Nicholas Lens , Belgian composer Josef Lense , physicist Jeremain Lens , Dutch Surinam footballer Other uses Laser engineered net shaping , a rapid prototyping technology capable of building fully dense metal parts Perspective cognitive Lens, a fictional alien device in E. E. Smith s Lensman series disambig surname an Lens de Lens es Lens eo Lens fr Lens it Lens nl Lens pms Lens pt Lens sco Lens simple Lens disambiguation sk Lens sv Lens tr Lens vo Lens ... more details
Infobox single See Wikipedia WikiProject Songs Name Into the Lens Cover Into the Lens.jpg Artist Yes band Yes Album Drama Yes album Drama B side Does It Really Happen? Released 1980 Format 7 Recorded Genre Progressive rock Length 3 47 Label Atlantic Records Atlantic Writer Geoff Downes , Trevor Horn , Steve Howe guitarist Steve Howe , Chris Squire , Alan White Yes drummer Alan White Producer Yes and Eddie Offord Chronology Last single Don t Kill The Whale br 1978 This single Into the Lens br 1980 Next single Owner of a Lonely Heart br 1983 Infobox single Name I Am a Camera Type Single Artist The Buggles from Album Adventures in Modern Recording Cover I Am A Camera Single Cover.jpg B side Fade Away Released October 1981 Format 7 , 12 Genre Synthpop Length 4 32 Label Carrere Records Carrere Writer Geoff Downes , Trevor Horn Producer Trevor Horn Last single Elstree song Elstree br 1980 This single I Am a Camera br 1981 Next single Adventures in Modern Recording song Adventures in Modern Recording br 1982 Into the Lens is a song originally written by Trevor Horn and Geoff Downes of The Buggles . It was first released as Into the Lens on the Yes band Yes album Drama Yes album Drama in 1980, and the year after on Adventures in Modern Recording , the second and last album of The Buggles. Both versions were also released as singles Into the Lens I Am a Camera by Yes in 1980 and I Am a Camera in October 1981 by The Buggles on Carrere Records . ref name AIMR Overview The first version of the song ... Howe guitarist Steve Howe , Chris Squire and Alan White Yes drummer Alan White , and therefore, Into the Lens ... I Am a Camera was a Buggles track and we had adapted it into a Yes track. It became Into the Lens and, naturally, slightly more overblown. I don t mind Into the Lens the melody s unadulterated while ... different lyrics, notably I will never let you go, and you always let the feelings show Into the Lens ... edit of Yes own Into the Lens was entitled Into the Lens I Am a Camera . The line I am a camera is a quote ... more details
Unreferenced date August 2009 A Celor lens is a highly corrected photographic lenslens of the Dialyt lens Dialyt type, designed for process photography , involving reproduction at or near 1 1 scale. DEFAULTSORT Celor Lens Category Photographic lenses optics stub ... more details
Unreferenced date December 2009 Image Canon EFS 18 to 55 m lense covers.JPG thumb Canon company Canon lens covers. File 62mm lens cap.jpg thumb Screw in metal lens cap A lens cover or lens cap provides protection from scratches and minor collisions for camera and camcorder photographic lens lenses . Lens covers come standard with most cameras and lenses. Some mobile camera phone s include lens covers, such as the Sony Ericsson W800 , the Sony Ericsson K750 and the Sony Ericsson K550 . 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. See also Lens hood DEFAULTSORT Lens Cover Category Photography equipment ... more details
Infobox French commune name Lens Lestang region Rh ne Alpes department Dr me arrondissement Valence canton Le Grand Serre INSEE 26162 postal code 26210 mayor Jean Pierre Olmos term 2008&ndash 2014 intercommunality Rh ne Valloire longitude 5.04333333333 latitude 45.2925 elevation m 300 elevation min m 237 elevation max m 448 area km2 16.41 population 801 population date 2008 Lens Lestang is a Communes of France commune in the Dr me Departments of France department in southeastern France . Population D mographie 1911 976 1962 609 1968 655 1975 636 1982 672 1990 629 1999 667 2008 801 See also Communes of the Dr me department References http www.insee.fr en home home page.asp INSEE reflist commonscat Dr me communes DEFAULTSORT Lenslestang Category Communes of Dr me Dr me geo stub ca Lens Lestang ceb Lens Lestang es Lens Lestang eu Lens Lestang fr Lens Lestang it Lens Lestang ms Lens Lestang nl Lens Lestang oc Lens Lestang pms Lens Lestang pl Lens Lestang pt Lens Lestang bug Lens Lestang uk vi Lens Lestang vo Lens Lestang war Lens Lestang ... more details
Bernard Lens may refer to one of three British artists Bernard Lens 1631 1708 , probably from the Netherlands , also the writer of several religious tracts Bernard Lens II 1659 1725 , son of the former, mezzotint engraver Bernard Lens III 1682 1740 , son of the former, portrait miniature portrait miniaturist Category Artist families Lens Category Portrait miniaturists Lens, Bernard Category British engravers Lens, Bernard ... more details
Refimprove date June 2011 File Lens flare scheme en.svg thumb Scheme of lens flare. Lens hood is designed in the way that it does not block the angle of view of the lens. Lens hoods block the sun or other light source in order to prevent glare and lens flare. File Tulip Lens Hood.jpg thumb A conical petal lens hood. In photography , a lens hood or lens shade is a device used on the end of a photographic lenslens to block the sun or other light source in order to prevent glare vision glare and lens flare . ref van Walree, Paul Lens hoods, http toothwalker.org optics lenshood.html ref The geometry of the lens hood can vary from a plain cylindrical or conical section much like a lamp shade to a more ... produce a reasonable good shade without blocking the field of view of the lens and thus producing vignetting . Properly petal shaped lens hoods produce more shade than normal lens hoods with the same end diameter. Square lens hoods may be even better. Lens hoods are more prominent in long focus lens es because the field of view has a smaller Angle of view viewing angle than of wide angle lens es. For wide angle lenses, the length of the hood away from the end of the lens cannot be as long as those for telephoto lenses because of the viewing angle. Lens hoods are often designed to fit onto the matching lens facing either forward, for normal use, or backwards, so that the hood may be stored with the lens without occupying much additional space. Some lens hoods are flexible and collapse for storage. In addition, they offer some physical protection for the lens due to the hood extending farther than the lens itself ref Harmer, Jim, http improvephotography.com 1101 lens hood purpose dslr What does a lens hood do? , Improve Photography , 15 Jun 2011 ref . gallery File Canon EF 70 200mm F2.8L lens with hood.jpg A conical petal lens hood used on the Canon EF 70 200mm lens . Note that from this angle no part of the glass lens surface is visible, as the line of sight is blocked by the lens ... more details
The Gauss lens consists of two lens optics lenses in its most basic form, a positive Lens optics Types of simple lenses meniscus lens on the object side and a negative meniscus lens on the image side. The Optical power power of the positive element predominates, but the negative element corrects for chromatic aberration . See also Double Gauss lens Category Lenses optics stub ... more details
additionalcitations date April 2011 A Lens Controller is device that controls motorized photographic lens functions such as Zoom lens zoom , Focus optics focus , and Iris diaphragm iris or aperture. ref Kruegle, Herman 2007 . CCTV Surveillance , Butterworth Heinemann. ref Lens controllers can be found internally in modern still camera photographic lens es and as a stand alone unit in machine vision , remote sensing , optoelectronics systems, and security applications. Internal Photographic Lens Controllers Internal lens controllers take information from the camera or lens elements and perform automatic ... zoom lens and used mainly for photography. Stand Alone Photographic Lens Controllers Stand alone lens controllers are attached to a photographic lens by a cable to allow operator manual control of lens functions. Machine Vision, CCTV, or Computer Vision Lens Controllers Lens controllers for machine ... there is no standard for wiring of lenses most have Direct Current DC motors attached to lens elements and are controlled with 6 VDC, 8 VDC or 12 VDC. Machine vision lens controllers come in manual or computerized varieties. Manual lens controllers are composed of switches and a power supply. When the operator actuates a switch , a function of the lens is enabled. Manual control requires an operator to view the image through the lens in which adjustment is taking place. Manual lens controllers are the most common and are frequently used in CCTV security systems. Computerized lens controllers ... interface. A remote computer sends a command to the lens controller through an RS232 , RS485 , USB , or Ethernet interface to actuate a lens function. The Lens Controller will then perform the command automatically. If a lens is equipped with presets, potentiometers attached to lens ... and move to a specific position. If the lens is not equipped with presets, then the controller can only move a lens function to an approximate position. References See Wikipedia Footnotes on how to create ... more details
Unreferenced stub auto yes date December 2009 In optics , a simple lens or singlet lens is a lens optics lens consisting of a single simple element. Typical examples include a magnifying glass or a lens in a pair of simple glasses reading glasses . Simple lenses are prone to aberration in optical systems aberrations , especially chromatic aberration . They cannot be used for precise imaging and make poor camera lens es. They are commonly used for laser applications, however, where the beams are both monochromatic minimizing chromatic aberration and narrow minimizing spherical aberration . Some camera s with Focus free lens fixed lenses have been made using a simple lens, usually a meniscus lens with the convex face facing outward. In such examples the lens aperture is made small and in some cases such as the Kodak Brownie camera Brownie 127 camera , the photographic film film plane is curved to reduce the impact of aberrations. See also Lens optics Doublet lens Aspheric lens DEFAULTSORT Simple Lens Category Photographic lenses Category Lenses Optics stub zh ... more details
In imaging optics, a field lens is a positive powered lens or group of lenses that comes after the objective lens and before the image plane or the eyepiece , serving to change the size of the image, ref http www.colorado.edu physics phys1230 phys1230 fa01 topic43.html Judah Levine, University of Colorado Physics 1230 Light and Color The Field Lens. Fall 2001 ref ref http spie.org x34410.xml SPIE Optopedia Field Lens ref or to provide image space telecentricity . Reference references optics stub Category Lenses Category Microscope components de Feldlinse ... more details
Image cambo lens board.jpg thumb right 200px Cambo lens board with Copal 1 A Lens board commonly spelled as lensboard is a photographic part used for securing a lens to the front standard of a large format view camera . The lens board itself is usually flat, square, and made of metal most commonly Aluminum or wood and sometimes plastic. The lens board will have a hole of various diameters drilled dead center on the board. A lens board typically varies between 1 and 4 millimeters in thickness. The overall size and shape of the lens board depends on the brand of camera and film format used. Some cameras will use 2 to 4 screws to secure the lens board to the front standard of the view camera, most commonly however, the lens board will be secured by one or more locking levers or tabs to allow tool less removal of the lens board. The rear surface of a lens board is usually painted matte black to keep light entering the camera through the lens during exposure from reflecting off the surface and interfering with the projected image. While most lens boards are flat, some are recessed to accommodate wider focal length lenses which must be positioned closer to the film plane . A recessed lens ... length of a particular lens, a certain diameter of hole must be drilled in the center of the lens board to accommodate the shutter photography shutter assembly . Lens boards are typically available pre drilled by the camera manufacturer, however, if no replacement lens board is available from a camera ... 1 41.6 mm Copal 3 65 mm Copal 3s 64.5 mm Lens mounting Image graphex lens board.jpg thumb right 200px 135mm Optar lens mounted on a 0 Speed Graphic lens board Lenses are fitted to a lens ... photography shutter assembly by threading a locknut to rear of the shutter. A front lens element will thread onto the mounted shutter and if necessary, a second lens element will thread onto the rear ... with the appropriate tools. Other uses Image enlarger lens board.jpg thumb right 200px Enlarging lens ... more details
Infobox Belgium Municipality name Lens picture Lens Hainaut L tang du moulin.jpg picture legend map Lens Hainaut Belgium Map.png map legend Location of Lens in Hainaut arms flag region BE REG WAL community BE FR province BE PROV HT arrondissement Arrondissement of Mons Mons nis 53046 pyramid date 0 19 20 64 65 foreigners foreigners date mayor Ghislain Moyart PS majority Socialist Party francophone Belgium PS , Reformist Movement MR postal codes 7870 telephone area 065 web http www.lens.be www.lens.be lat deg 50 lat min 33 lon deg 03 lon min 54 Lens is a Wallonia Walloon municipality located in the Belgium Belgian province of Hainaut province Hainaut . In 2007 its population was 4042. ref http statbel.fgov.be downloads pop200701com.xls Werkelijke bevolking per gemeente op 1 januari 2007 Population de droit par commune au 1 janvier 2007 .xls ref The total area is 49.42 km which gives a population density of 80 inhabitants per km . It is located at 50 33 North, 03 54 East, alongside the N56 road Belgium N56 road . ref http statbel.fgov.be pub d1 p120 nl.xls Geografische co rdinaten van de gemeenten .xls ref References Reflist Hainaut Hainaut geo stub Category Municipalities of Hainaut province br Lens Belgia bg ca Lens B lgica de Lens Belgien eo Lens Belgio fa fr Lens Belgique it Lens Belgio nl Lens Belgi pt Lens B lgica ro Lens Belgia ru simple Lens Belgium sk Lens Belgicko vi Lens, Hainaut vo Lens Belg n wa Linse war Lens, Belhika ... more details
DISPLAYTITLE Lens genus Taxobox name Lens image Illustration Lens culinaris0.jpg image width 200px image caption Lens culinaris regnum Plantae unranked divisio Angiosperms unranked classis Eudicots unranked ordo Rosids ordo Fabales familia Fabaceae subfamilia Faboideae tribus Fabeae genus Lens genus authority Mill. subdivision ranks Species subdivision Lentil Lens culinaris Lentils br Lens ervoides br Lens lamottei br Lens nigricans br td tr tr td Ref http www.ildis.org ILDIS Version 6.05 The genus Lens of the legume family Fabaceae contains four species of small, erect or climbing herb s with pinnate Leaf leaves and small inconspicuous white flower s and small flattened pods. The edible seed s of Lens species are referred to as lentil s the lentil most commonly eaten is the seed of Lens culinaris . External links http gisweb.ciat.cgiar.org GapAnalysis ?p 271 Crop Wild Relatives Gap Analysis Portal reliable information source on where and what to conserve ex situ , regarding Lens genepool DEFAULTSORT Lens Genus Category Faboideae Faboideae stub az M rcim k cins ca Lens g nere da Linse sl gten de Linsen dsb Sok rod es Lens planta fr Lens genre hy hsb Sok r d it Lens botanica ka lt L is augalas ru sv Linssl ktet vi Lens genus ... more details
Image Cylindrical lenses.jpg thumb Cylindrical lenses. Image CylindricalLenses 2.png thumb 300px Diagram showing cylindrical lenses. br A Plano Convex cylindrical lens br B Plano Concave cylindrical lens A cylindrical lens is a lens optics lens which Focus optics focus es light which passes through on to a line instead of on to a point, as a Lens optics spherical lens would. The curved face or faces of a cylindrical lens are sections of a Cylinder geometry cylinder , and focus the image passing through it onto a line parallel to the intersection of the surface of the lens and a plane tangent to it. The lens compresses the image in the direction perpendicular to this line, and leaves it unaltered in the direction parallel to it in the tangent plane . Cylindrical lenses can be used to correct astigmatism eye ocular astigmatism , although toric lens es are more commonly used. They can also potentially be used in solar water heating installations, such as a plastic pillow type solar water heater. They are used to correct the output from diode laser s, to produce a round beam from the diode s elliptical output. Sources Jacobs, Donald H. Fundamentals of Optical Engineering. McGraw Hill Book Co., 1943. Category Lenses optics stub de Zylinderlinse nl Cilindrische lens ... more details
Breathing refers to when a lens optics lens optics change the apparent focal length slightly when shifting the mechanical focus optics focus . Some often more expensive lenses are designed to lessen the degree this effect. Lens breathing does not prevent one from racking focus or follow focus following focus with this lens, but it lessens the desirability of any type of focus adjustment, since it noticeably changes the composition of the shot. Not to be confused with the suction and expulsion of air from within the lens as its internal volume changes. DEFAULTSORT Breathing Lens Category Film and video terminology Filming stub ... more details
Primary lens redirects here. See also prime lens . In photography , a secondary lens is a photographic lenslens designed to be used in conjunction with another lens, called the primary lens . A secondary lens may be designed to be used either in front of the primary lens, between it and the subject, or behind the primary lens, between it and the film. Secondary lenses are typically simpler in mechanical ... of Focus optics focus or aperture , as these are achieved by the controls on the primary lens. Lenses used in front of the primary lens Examples of secondary lenses designed to be used in front of the primary lens are Fisheye lens Fisheye adaptors Corrected wide angle lens wide angle adaptors Telephoto adaptors such as teleside converter s Close up lens es All of these typically mount on the filter ring of the primary lens. Front mounting secondary lenses are commonly used to provide wide angle and telephoto lenses for cameras which lack the facility to change the primary lens, such as consumer ... the primary lens Teleconverters main teleconverter The most common secondary lens used behind the primary lens is the teleconverter . A typical teleconverter has a male and a female lens mount of the same type, to allow it to be used between a primary lens and a camera body of the matching system. The resulting combination has a greater focal length than the primary lens alone, and the same absolute ..., and when used in this combination deliver quality comparable to the primary lens. Others are general purpose, and in use typically offer less image quality then a primary lens of the same quality ... adaptor, as the angle of view of the primary lens is matched to the film format for which is designed ... to use the primary lens for wider angles than those for which it is designed is therefore likely to cause ... lens to adapt a lens of one camera system and or film format to another. These are called active adaptors or converters. For example, a Pentax screw mount lens cannot normally be mounted on a Nikon ... more details
Image Imgageinverting 1.png thumb right Cross section of relay lens assembly System 1. Image Imageinverting 2.png thumb right Cross section of relay lens assembly System 2. Image Image erecting system.png thumb right Image erecting optical system for astronomical telescopes Erecting eyepiece . In optics, a relay lens is a lens or lens group that inverts an image and extends the optical tube. Relay lenses are found in endoscope s and periscope s for the purpose of extending the system, and before eyepiece s for the purpose of inverting an image. They may be made of one or more conventional lenses or achromatic doublet s, or a long cylindrical GRIN gradient index of refraction lens a GRIN lens . Relay lenses operate by producing intermediate planes of focus. For example, an objective lens such as an SLR lens produces an image plane where the image sensor would usually go. If you place a lens with focal length f a distance 2 f from that image plane and then put an image sensor 2 f beyond the lens, that lens will relay the first image to the second with 1 1 magnification see Lens optics Imaging properties Lens imaging properties . Ideally, this second image plane will be identical to the first, so you could put a sensor there and record the exact same image. If a longer distance is needed, this can be repeated. In practice, the lens will be an achromatic doublet . Also, for endoscope applications, where small tube diameter is desirable, most of the tube is filled with glass, with thin air gaps to allow for powered surfaces because marginal ray angle is smaller at a given numerical aperture the higher the index of refraction , this allows the relay to have higher NA for a given diameter. These are known as Hopkins rod lenses . External links Lens erecting systems. http www.tpub.com content misc manuals 2 TM 9 258 TM 9 2580106.htm Image erecting systems http i916.photobucket.com ... EBchecked topic 496947 relay lens Category Lenses Optics stub ... more details
Unreferenced stub auto yes date December 2009 In geology a lens is a body of ore or Rock geology rock or a deposit that is thick in the middle and thin at the edges, resembling a convex lens in cross section. Adjective lenticular . A lens can also refer to an irregular shaped formation consisting of a porous , Permeability fluid permeable sedimentary deposit surrounded by impermeable rock. DEFAULTSORT Lens Geology Category Petrology Category Sedimentology it Lente geologia uk Geology stub ... more details
Unreferenced stub auto yes date December 2009 Lens sag is a problem that sometimes afflicts very large refracting telescope Technical considerations refracting telescope s. It is the equivalent of mirror sag in reflecting telescope s. It occurs when the physical weight of the glass causes a distortion in the shape of the lens optics lens because the lens can only be supported by the edges. A mirror on the other hand can be effectively supported by the entire opposite face, making mirror sag much less of a problem. One expensive solution to lens sag is to place the telescope in orbit around the Earth . The technical limit concerning lens sag was reached at the Yerkes refractor 1897 with an aperture of 40 102 cm , where the sagging already causes small optical distortions. The 1890ies therefore mark the end of the great refractor s era. DEFAULTSORT Lens Sag Category Telescopes Optics stub de Durchbiegung Linse ... more details
Infobox Anatomy Name Crystalline lens anatomy Latin lens crystallina GraySubject 226 GrayPage 1019 Image ... point of a near object being brought to a focus by changing the curvature of the lens. Image2 Schematic ... Artery Vein Nerve Lymph MeshName Crystalline lens MeshNumber DorlandsPre l 06 DorlandsSuf 12483326 The crystalline lens is a transparent, Lens optics Types of simple lenses biconvex structure in the eye that, along with the cornea , helps to refract light to be Focus optics focused on the retina . The lens ... on the retina. This adjustment of the lens is known as Accommodation eye accommodation see also ... lens lenses . The lens is flatter on its anterior side. The lens is also known as the aquula Latin, a little stream , dim. of aqua , water or crystalline lens . In humans, the refractive power of the lens in its natural environment is approximately 18 dioptre s, roughly one third of the eye s total power. Position, size, and shape The lens is part of the anterior segment of the eye. Anterior to the lens is the iris anatomy iris , which regulates the amount of light entering into the eye. The lens is suspended in place by the Zonule of Zinn suspensory ligament of the lens , a ring of fibrous tissue that attaches to the lens at its equator ref http www.biology online.org dictionary Equator of lens ref ref http medical dictionary.thefreedictionary.com equator of the crystalline lens ref and connects it to the ciliary body . Posterior to the lens is the vitreous body , which, along with the aqueous humor on the anterior surface, bathes the lens. The lens has an ellipsoid, biconvex shape. The anterior surface is less curved than the posterior. In the adult, the lens is typically ... that the size and shape can change due to accommodation and because the lens continues to grow ... 1790 6 ref Variations among vertebrates In many aquatic vertebrates, the lens is considerably thicker ... 677 . Boston McGraw Hill ref Even among terrestrial animals, however, the lens of primate s such as humans ... more details
Unreferenced stub auto yes date December 2009 Orphan date December 2009 The coverage of a lens optics lens is the size of the image it can produce, measured as the diameter of the image circle produced by the optics. In a camera system the coverage must be large enough to cover the sensor or film used. In a view camera system, because the photographic film film plane can be moved independently of the lens plane, the lens must have enough coverage to cover the film while it is offset from the center of the coverage area. Inadequate coverage can lead to vignetting . DEFAULTSORT Coverage Lens Category Science of photography Photo stub ... more details
Unreferenced auto yes date December 2009 A lens lantern is a small, self contained lamp structure which may sometimes be used to serve as a lighthouse . Unlike a regular Fresnel lens , the lantern requires no housing to protect it from the weather its glass sides would refraction refract and magnify the light in the same fashion as would the lens. Lens lanterns were popular alternatives to lighthouses in the nineteenth century they required less care, were cheaper to erect, and could be fairly easily placed. See also F. Ross Holland, Jr. America s Lighthouses Their Illustrated History Since 1716 . DEFAULTSORT Lens Lantern Category Lighthouses Pharology stub ... more details
Unreferenced date October 2006 Image Panotools5618.jpg thumb 250px curvilinear perspective Curvilinear above and rectilinear below image. Notice the barrel distortion typical for fisheye lens es in the curvilinear image. While this example has been rectilinear corrected by software, high quality wide angle lens es are built with optical rectilinear correction. 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 opposed to being curved. In other words, it is a lens with little or no barrel or pincushion Image distortion distortion . At particularly wide angles, however, the rectilinear perspective will cause objects to appear increasingly stretched and enlarged as they near the edge of the frame. These types of lenses are often used to create forced perspective effects. The vast majority of video and still cameras use lenses that produce nearly rectilinear images. A popular alternative type of lens is a fisheye lens which produces a distinctly curvilinear, wide angle lens wide angled result. See also Rectilinear grid Rapid Rectilinear Gnomonic projection Nikkor 13mm f 5.6 DEFAULTSORT Rectilinear Lens Category Photographic lenses pt Objetiva retil nea Photo stub ... more details
about varifocal camera lenses corrective eyeglass lenses Progressive lens A varifocal lens is a camera lens with variable focal length in which Focus optics focus changes as focal length and magnification changes, as compared to parfocal lens parfocal true zoom lens , which remains in focus as the lens zooms focal length and magnification change . Many so called zoom lenses, particularly in the case of fixed lens cameras, are actually varifocal lenses . ref cite web url http www.rogercavanagh.com helpinfo 30 parfocal.stm title Parfocal Lenses accessdate 2007 11 18 last Cavanagh first Roger date 2003 05 29 archiveurl http web.archive.org web 20071007070643 http www.rogercavanagh.com helpinfo 30 parfocal.stm Bot retrieved archive archivedate 2007 10 07 ref Image Varifocal example.jpg thumb 500px none A varifocal lens. Left image is at 2.8mm, in focus. Middle image is at 12mm with the focus left alone from 2.8mm. Right image is at 12mm refocused. The close knob is focal length and the far knob is focus. References Footnotes reflist Notations cite web url http www.tokina usa.com glossary.html title Lens Glossary accessdate 2007 11 18 work Tokina Industrial, Inc. optics stub Category Photographic lenses es Varifocal ja pt Lente varifocal ... more details
Encyclopedia
top
