lens

Englisch - Türkisch

Definition von lens im Englisch Türkisch wörterbuch

{i} objektif

Tom, gözlüğünün camlarını ılık, sabunlu suyla yıkayıp onları bir bezle kuruttu. - Tom washed the lenses of his glasses with warm, soapy water and dried them on a cloth.

gözlük camı

göz merceği

telescopic lens dürbün gibi fotoğraf makinası objektifi

{i} adese

achromatic lens renksiz mercek

wideangle lens geniş açılı mercek

crystalline lens göz merceği

(Tıp) lens crystallina

{i} foto. objektif

{i} lens

(Tıp) Mercimek, lentil

geniş bir alanın resmini yakın bir mesafeden çekmek için kul

lens hood

(Fotoğrafçılık) parasoley

lens aperture

(Bilgisayar) diyafram

lens hood

(Sinema) parasol

lens hood

(Fotoğrafçılık) ışık siperliği

lens hood parasol

güneş diyaframı, güneşlik

lens release

Lens serbest

lens aperture

(Askeri) DİYAFRAM AÇIKLIĞI: Bir mercek diyaframı veya başka bir cihazda mercekten geçen ışık miktarını sınırlayan nisbi açıklık

lens coating

(Askeri) MERCEK KAPLAMASI: Bir mercek unsurunun üzerine kaplanan ince şeffaf tabaka

lens coating

(Fotoğrafçılık) objektif kaplaması

lens coating

(Askeri) mercek kaplaması

lens control

(Bilgisayar) mercek denetimi

lens distortion

(Askeri) mercek bozukluğu

lens distortion

(Askeri) MERCEK BOZUKLUĞU: Mercek bozukluklarından ve kaymalarından dolayı meydana gelen görüntü kaymaları

lens maker

gözlükçü

lens outsert

(Çevre) mercek koruyucu

lens response

izin verilmeyen

lens spotlight

(Aydınlatma) mercekli projektör

lens used

(Bilgisayar) kullanılan mercek

compound lens

(Fotoğrafçılık) bileşik objektif

conversion lens

(Fotoğrafçılık) açılı mercek

convex lens

(Bilgisayar,Fizik) ince kenarlı mercek

diffuser lens

flu mercek

eye lens

(Anatomi) göz merceği

len

(Bilgisayar) uzunluk

Maksimum uzunluk: 200 kelime. - Maximum length: 200 words.

Trigonometri üçgenlerin uzunluklarını ve açılarını içeren ilişkileri çalışmaktadır. - Trigonometry studies relationships involving lengths and angles of triangles.

lense

mercek

mirror lens

(Fotoğrafçılık) aynalı objektif

supplementary lens

ek mercek

wide angle lens

(Fotoğrafçılık) geniş açı objektif

wide aperture lens

(Sinema) büyük açıklıklı mercek

zoom lens

(Fotoğrafçılık,Teknik) değişir odaklı mercek

anastigmatic lens

apochromatic lens

Kontak lenslerimi arıyorum. - I'm looking for my contact lens.

Kontakt lens kullanıyorum. - I wear contact lenses.

electromagnetic lens

elektromanyetik mercek

electron lens

çınca merceği

electrostatic lens

interchangeable lens

değiştirilebilir mercek

fotoğraf büyüten mercek

Fresnel lens spotlight

Fresnel projektörü, Fresnel ışıldak

achromatic lens

şeffaf lens

diffusing lens

flu mercek, yumuşak odaklı mercek

pozitif mercek, yakınsak mercek

projection lens

projeksiyon merceği, gösterici merceği

telephoto lens

foto. ırak merceği, teleobjektif

twin lens scanner

çift mercekli tarayıcı

variable focus lens

zum merceği, değişir odaklı mercek

waveguide lens

dalga kılavuzu merceği

zoom lens

foto. değişir odaklı mercek, zoom objektifi

achromatic lens

akromatik mercek,şeffaf lens

kamera merceği,mercek

centered lens

(Fotoğrafçılık) merkezlenmiş mercek

collimating lens

kosutlayici mercek

concave lens

çukur mercek,içbükey lens

(Elektrik, Elektronik) dielektrik radar merceği

electron lens

elektron mercegi

electron lens

(Teknik,Televizyon) elektronik mercek

electron lens

elektron merceği

electronic lens

(Elektrik, Elektronik,Teknik) elektronik mercek

fresnel lens optical landing system

(Askeri) fresnel lensli optik iniş sistemi

hand lens

el merceği

i'd like a lens

objektif rica ediyorum

i'd like a lens cap

objektif kapağı rica ediyorum

immersion lens

(mikroskop) daldırma merceği

intermediate lens

(İnşaat) ara mercek

(İnşaat) görüntü merceği

parallel plate lens

paralel levhali mercek

portrait lens

(Sinema) pozitif ek mercek

(Sinema) gösterici merceği

projector lens

(İnşaat) projektör merceği

tele conversion lens

(Fotoğrafçılık) uzak açı lens

telephoto lens

teleobjektif, uzakçeker

twin lens reflex

(Fotoğrafçılık) çift objektifli refleks

zoom lens

{i} zoom merceği

zoom lens

{i} değişken odaklı mercek

Türkisch - Türkisch

Definition von lens im Türkisch Türkisch wörterbuch: Göze takılan mercek; Kontak lens; Mercek; bakınız: Kontak lens
LEN: (Osmanlı Dönemi) Gr: (Muzâri fiilini nasbeden edatlardan birisi). Bir işin aslâ olamıyacağını ifade eder: $ cümlesinde; kâfirler aslâ Cennete giremezler, derken olduğu gibi. (Bak: Huruf-u nâsibe
kontak lens: Gözün saydam tabakasının üzerine doğrudan uygulanan, görmeyi düzeltici mercek

Englisch - Englisch

Definition von lens im Englisch Englisch wörterbuch: A device which focuses or defocuses electron beams; To become thinner towards the edges; To film, shoot; A convex shape bounded by two circular arcs, joined at their endpoints, the corresponding concave shape being a lune; The transparent crystalline structure in the eye; An object, usually made of glass, that focuses or defocuses the light that passes through it; A way of looking, literally or figuratively, at something
If the public looks at the condition of America's children largely through a negative lens, worries Child Trends , it may be more difficult to promote child well-being..; A genus of the legume family; its bean; {n} a glass which diverts the rays of light form a direct course; the transparent, dual-convex body which focuses light rays onto the retina (See "Anatomy of the Eye" on the MD Support web site ); The lens sits in the middle of the eye, behind the pupil It focuses the light onto the retina so that you see clear images The lens is a remarkable instrument that adjusts from reading fine print to reading a movie marquee 100 or more feet away Tiny ligaments keep the lens suspended in place (Marks 3); (metaphor) a channel through which something can be seen or understood; "the writer is the lens through which history can be seen"; A structure inside the eye that helps to focus light on the retina It is curved on both sides and acts similar to a camera lens; One or more pieces of optical glass or similar material designed to collect and focus rays of light to form a sharp image on the film, paper, or projection screen; A cylinder of shaped pieces of glass or plastic at the front of a camera, the lens projects a tiny image of the subject onto the film; a part of the eye that provides some focusing power The lens is able to change shape allowing the eye to focus at different distances; Transparent biconvex tissue within the eye that helps bring rays of light to focus on the retina The lens crystalline can change shape and increase the optical power of the eye when viewing near objects This ability to accommodate is lost after age 40, requiring the use of bifocals or reading glasses; The crystalline lens of the eye is located behind the pupil and iris of the eye and its job is to flex and bend to help focus the light coming in The lens relaxes and contracts when focused at near and far distances to apply more or less "zoom" power in order to see object clearly This structure is generally quite clear and cannot be seen without special equipment If it gets cloudy, we refer to this as a "cataract " SEE: ACCOMMODATION; A combination of shaped glasses and air spaces set in a specific arrangement within a barrel Within the lens is a diaphragm that can be opened and closed to allow in specific amounts of light This is controlled manually by a ring on the outside of the lens barrel, or electronically via pins in the coupling ring that mounts the lens to the camera Lenses have two primary functions: one is to focus light with as little distortion or aberration as possible on to film or sensor Focusing is accomplished by changing the relationship of the elements in the lens to the film plane The other function is to control the amount of light hitting the film by use of its aperture Autofocusing lenses may contain small motors for racking the lens back and forth in response to changes in focus; the transparent structure inside the eye that focuses light rays onto the retina; a transparent optical device used to converge or diverge transmitted light and to form images electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons biconvex transparent body situated behind the iris in the eye; it focuses light waves on the retina (metaphor) a channel through which something can be seen or understood; "the writer is the lens through which history can be seen"; (also called crystalline lens) - the transparent structure inside the eye that focuses light rays onto the retina; biconvex transparent body situated behind the iris in the eye; it focuses light waves on the retina; A transparent, biconvex, nearly spherical body in the eye which focuses light passing through the pupil (images) onto the retina; electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons; In practice, the curved surfaces are usually spherical, though rarely cylindrical, or of some other figure; To film; A transparent double convex (outward curve on both sides) structure between the iris and the vitreous humor Two structures of the eye focus light onto the retina The first is the cornea or front surface of the eye that provides about 65% of the focusing power of the eye The human lens is located behind the iris and in front of the vitreous humor and provides the remaining focusing power for the eye In younger patients (usually below age 45) the lens is able to adjust it's power allowing the eye to change it's focal length from distance to near; A medium which will bend light The eye has its own crystalline lens that helps focus light Spectacle lenses help bend the light in such a way that once it reaches the eye it can then be focused Contact lenses do the same except that they are in contact with the eyeball; A structure made of transparent glass or other material, with at least one curved surface, which causes the light rays passing through it to converge or diverge in a controlled fashion; The crystalline lens finishes the focusing of light It helps to "fine tune" vision, and it is able to change shape to allow the eye to focus on near objects When it becomes cloudy, it is called a cataract Unlike the cornea, the lens can be made to change its shape (and, therefore, its refractive power) rapidly and voluntarily Using its ability to change shape, the lens allows the eye to change its focal point Changes in the shape of the lens will allow a normal eye to focus on near objects; A lens is a clear object which changes the direction of light beams passing through it There is a part of the eyeball called the lens, which focuses light on the retina Corrective lenses, such as contact lenses and eyeglass lenses, change the direction of incoming light so that a clear image appears on the retina and you can see clearly; a transparent optical element, so constructed that it serves to change the degree of convergence or divergence of the transmitted rays; A lens is a thin curved piece of glass or plastic used in things such as cameras, telescopes, and pairs of glasses. You look through a lens in order to make things look larger, smaller, or clearer. a camera lens I packed your sunglasses with the green lenses; The transparent, crystalline, flexible structure in the front of the eye directly behind the pupil Tiny muscles change the shape of the lens to bend the entering light, helping the eye focus for seeing up close and far away; A piece of glass, or other transparent substance, ground with two opposite regular surfaces, either both curved, or one curved and the other plane, and commonly used, either singly or combined, in optical instruments, for changing the direction of rays of light, and thus magnifying objects, or otherwise modifying vision; The glass or plastic element through which light first enters your camera If you have a poor-quality lens, it doesn't matter how many megapixels or other features a camera has, the picture will be poor Plastic lenses can make your photo look as though they were taken on a foggy day Aspherical glass lenses produce better pictures by reducing the slight distortion often caused by circular lenses; is a part of the eye that provides some focusing power The lens is able to change shape allowing the eye to focus at different distances; a transparent optical device used to converge or diverge transmitted light and to form images; The part of the eye behind the iris that adjusts focus for different distances by changing shape; {i} piece of transparent material having two opposite surfaces which refract rays of light to form an image; part of the eye which focuses light rays to form an image on the retina; The transparent structure in the front of the eye With outward curves on both sides, the lens helps focus light on the retina A piece of glass or other transparent material having two polished opposite surfaces, at least one of which is curved; One or more pieces of optical glass used to gather and focus light rays to form an image; An optical device made of glass or other transparent material that forms images by bending and focusing rays of light A lens made of a single piece of glass cannot produce very sharp or exact images, so camera lenses are made up of a number of glass "elements" that cancel out each other's weaknesses and work together to give a sharp true image The size, curvature and positioning of the elements determine the focal length and angle of view of a lens; In your eye, the lens is the part behind the pupil that focuses light and helps you to see clearly. see also contact lens, telephoto lens, wide-angle lens, zoom lens. Piece of glass or other transparent substance that is used to form an image of an object by converging or diverging rays of light from the object. Because of the curvature of its surface, different rays of light are refracted (see refraction) through different angles. A convex lens causes rays to converge on a single point, the focal point. A concave lens causes rays to diverge as though they are coming from a focal point. Both types cause the rays to form a visual image of the object. The image may be real inverted and photographable or visible on a screen or it may be virtual erect and visible only by looking through the lens; genus of small erect or climbing herbs with pinnate leaves and small inconspicuous white flowers and small flattened pods: lentils
lens blank: A rough, opaque piece of glass of suitable size, design and composition for use, when ground and polished, as a multifocal lens for use in a pair of eyeglasses
lens blanks: plural form of lens blank
lens board: A part used for securing a lens to the front standard of a large-format view camera
lens boards: plural form of lens board
lens flare: A stray patch of brightness in a photographic image resulting from aberrant refractions or reflections within the lens due to an exceptionally bright light source, sometimes one just outside the image proper. Lens flare is usually unwanted, but can be exploited for artistic effect
lens hood: (Fotoğrafçılık) In photography, a lens hood is a device used on the end of a lens to block the sun or other light source in order to prevent glare and lens flare
lens cap: cap used to keep lens free of dust when not in use
lens capsule: a tenuous mesoblastic membrane surrounding the lens
lens implant: a clear plastic lens implanted in the eye; usually done when the natural lens has been removed in a cataract operation
Len: A diminutive of the male given name Leonard
achromatic lens: A lens generally composed of two separate lenses, one convex and one concave and generally of different materials, in such a way that the chromatic aberration produced by one is corrected by the other
contact lens: A thin lens, made of flexible or rigid plastic, that is placed directly on to the eye to correct vision, used as an alternative to spectacles, or, if coloured, to change one's eye color cosmetically
contact-lens: Attributive form of contact lens, noun
contact-lens case.
convex lens: A lens having at least one convex surface, such that light passing through it may be brought to a focus
gravitational lens: A massive body that produces distorted, magnified or multiple images of more distant objects when its gravitational field bends the path of light rays
lense: Common misspelling of lens. (presumably a back-formation from the plural lenses)
lensed: Having a (specified form of) lens
lensing: The focussing of light as if by a lens
macro lens: A lens that allows a camera to focus at very close range to photograph small objects
magnetic lens: a magnetic field with axial symmetry capable of converging a beam of charged particles of uniform velocity and of forming images of objects placed in the path of such beam
varifocal lens: A spectacle lens whose magnifying power varies from top to bottom, allowing them to be used for both distance use and for reading
wide-angle lens: A short focal length lens having a wide angle of view
zoom lens: a mechanical assembly of lenses whose focal length can be rapidly changed
Fresnel lens: Series of concentric rings, each consisting of a thin part of a simple lens, assembled on a flat surface. G.-L.-L. Buffon (1748) first had the idea of dividing a lens surface into concentric rings to reduce the weight. In 1820 his idea was adopted by Augustin-Jean Fresnel (1788-1827) for the construction of lighthouse lenses. Fresnel lenses have the optical properties of much thicker and heavier lenses. They are used in spotlights, floodlights, railroad and traffic signals, and decorative lights. Some thin Fresnel lenses are molded in plastic, the width of the rings being only a few thousandths of an inch; such lenses are used in cameras and small projectors
Len: a diminutive of Leonard
achromatic lens: A composite lens, of two (or three) different kinds of glass, designed to reduce chromatic aberration
achromatic lens: Lens for which all light colors have the same focal length
achromatic lens: a lens corrected for black and white photography; specifically one that brings visual rays to the same focus
achromatic lens: A refractor lens, made of two or sometimes three separate lenses, which has the effect of bringing most of the viewed colours to a sharp focus, thus reducing chromatic aberration Finder Scope: A low power telescope attached parallel to the main instrument which provides easy object locating and telescope aiming
achromatic lens: An Achromatic lens is a system of lenses joined in order to minimize color and shape distortions (chromatic and spherical aberrations) that are inherent in a single lens system
achromatic lens: A combination of lenses made of different glass, used to produce images free of chromatic aberrations
achromatic lens: lens composed usually of two separate lenses used to produce images free of chromatic aberrations
achromatic lens: Refers to a lens which has been partly corrected for chromatic aberration Such a lens is customarily made to bring green and red light rays to approximately the same point focus Also called an achromat
achromatic lens: a compound lens system that forms an image free from chromatic aberration
anastigmatic lens: a lens designed to correct astigmatism
bi-concave lens: double concave lens, lens curved inward like a bowl on both sides
camera lens: a lens that focuses the image in a camera
closeup lens: a photographic lens with a short focal length used to take pictures at short ranges
compound lens: a lens system consisting of two or more lenses on the same axis
concave lens: lens which is rounded inward
contact lens: {i} small plastic or glass lens placed directly on the cornea of the eye on top of the iris to correct a vision problem or for cosmetic purposes
contact lens: Contact lenses are small plastic lenses that you put on the surface of your eyes to help you see better, instead of wearing glasses. A thin plastic or glass lens that is fitted over the cornea of the eye to correct various vision defects. a small round piece of plastic that you put on your eye to help you see clearly. Thin artificial lens worn on the surface of the eye to correct refractive defects of vision. Early glass contact lenses, invented in 1887, were uncomfortable and could not be worn long. Plastic-based lenses, made to measurements of corneal curvature taken by optical instruments, were first developed in the mid 20th century. Gas-permeable lenses allow more oxygen to reach the eye, thus increasing comfort and wear time. Contact lenses have advantages over eyeglasses for certain visual defects and may be preferred for the sake of appearance and other reasons
contact lens: A thin, bowl shaped lens worn on the surface of the eye
contact lens: Lens made of glass or plastic designed to maintain contact on the surface of the cornea Usually used to correct refractive error
contact lens: a thin curved glass or plastic lens designed to fit over the cornea in order to correct vision or to deliver medication
converging lens: lens such that a beam of light passing through it is brought to a point or focus
converging lens: lens which merges light rays together, lens which concentrates light
convex lens: rounded lens, lens which merges light rays together
crown lens: The crown-glass element in an achromatic lens
crown lens: a lens made of optical crown glass
crystalline lens: The lens of an eye
dioptric lens: lens which refracts light
dispersing lens: lens which divides light into rays of different colors
divergent lens: lens that changes the course of rays of light
diverging lens: a lens such that a parallel beam of light passing through it is caused to diverge or spread out
electron lens: Any of various devices that use an electric or magnetic field to focus a beam of electrons
eye lens: {i} lens of an ocular which is nearest to the eye
field lens: the lens that is farthest from the eye in an optical device with morethan one lens
field lens: The lens positioned farthest from the eye in a compound eyepiece
fish-eye lens: a type of curved lens (=piece of glass on the front of a camera) that allows you to take photographs of a wide area
fresnel lens: See under Lens
fresnel lens: lens composed of a number of small lenses arranged to make a lightweight lens of large diameter and short focal length
gravitational lens: A massive celestial object, such as a galaxy, whose gravity bends and focuses the light of a more distant object, resulting in a magnified, distorted, or multiple image of the original light source for a distant observer
hand lens: A hand-held magnifying glass
intraocular lens: an artificial lens that is implanted into the eye of someone to replace a damaged natural lens or someone who has had a cataract removed
len: Large Extension Node
len: Line Equipment Number
len: The length function returns an integer representing the number of characters contained in its string argument
len: FR-NB linge
len: >>> len(x) 7
len: lend
lense: misspelling of lens
lense: a transparent optical device used to converge or diverge transmitted light and to form images
lenses: A set of tools in the form of glasses, contacts or vision therapy equipment used by eye doctors to compensate for refractive error and administer passive or aggressive vision therapy
lenses: plural of lens
lenses: Lenses are devices that redirect light In photography, lenses are used to focus an image for the film Holographers use lenses to widen a laser's beam to illuminate all of the object being holographed
lenses: A glass gas pump globe insert that fits into a globe body; usually decorated with the word "Gasoline," or an oil company logo or name
lenses: Pieces of glass or other transparent materials used for magnification or increased visual acuity See Free Eye Tests
lenses: What kind of lens can I use with REALViZ Stitcher?
lensing: present participle of lens
object lens: first lens that receives the image of an object (in a microscope, etc.)
objective lens: The lens closest to the object In a stereo (low power) microscope there are objective pairs, one lens for each eyepiece lens This gives the 3-D effect On a high power binocular model there is still only one objective lens so no stereo vision
objective lens: The large lens at the front end of a viewing system
objective lens: – in a compound microscope or a telescope, the lens closest to the object being viewed
objective lens: The second of two figures quoted on a pair of binoculars that indicates the diameter of the lens furthest away from your eye when you're looking through them It's quoted in millimeters and the first figure is the magnification A 10x50 pair, for example, has 10x magnification with a 50mm objective lens
objective lens: The lens of the eyepiece The ratio of the focal length of the objective lens to that of the mirror determines the magnification
objective lens: In an optical device using compound lenses, the lens closest to the object observed
objective lens: The primary light gathering optic of a refraction telescope, located opposite of the eyepiece
portrait lens: a compound camera lens with a relatively high aperture
telephoto lens: A telephoto lens is a powerful camera lens which allows you to take close-up pictures of something that is far away. a long lens that you put on a camera so that you can take clear photographs of things that are a long way away
telephoto lens: a camera lens that magnifies the image
twin-lens reflex camera: camera with two objective lenses of the same focal length where one lens is the actual lens that takes the picture amd the other is used for the viewfinder system
wide-angle lens: a camera lens having a wider than normal angle of view (and usually a short focal length); produces an image that is foreshortened in the center and increasingly distorted in the periphery
wide-angle lens: A wide-angle lens is a lens which allows you to photograph a wider view than a normal lens. a camera lens that lets you take photographs with a wider view than normal
zoom lens: A lens of adjustable focal length You zoom to increase or decrease the lens's magnifying power, making the subject bigger or smaller in the frame
zoom lens: a lens in which the focal length can be adjusted over a wide range, giving the photographer, in effect, lenses of many focal lengths
zoom lens: a camera lens that magnifies the image
zoom lens: Lens with variable focal length within a certain range
zoom lens: {i} system of lenses that can be rapidly adjusted for close or distant shots while keeping the image in focus
zoom lens: A zoom lens is a lens that you can attach to a camera, which allows you to make the details larger or smaller while always keeping the picture clear. A camera lens whose focal length can be rapidly changed, allowing rapid change in the size of an image. a camera lens that can change from a distant to a close view
zoom lens: A lens of continuously variable focal length
zoom lens: A lens that lets you change focal lengths on the fly
zoom lens: A lens in which you adjust the focal length over a wide range In effect, this gives you lenses of many focal lengths
zoom lens: A lens of adjustable focal length You can zoom to increase or decrease the lens' magnifying power, making the subject bigger or smaller in the frame
zoom lens: A lens with a focal length that can be changed during a shot A shift towards the telephoto range enlarges the image and flattens its planes together, giving the impression of moving into the scene's space, while a shift toward the wide-angle range does the opposite
zoom lens: A lens with the ability to change its focal length manually or through the use of a controller to cover a variety of needs
zoom lens: An adjustable lens to a range of focal lengths
zoom lens: A lens with several moving elements which can be used to produce a continuous range of focal lengths
zoom lens: A lens on which the focal length can be varied, as opposed to a fixed focal length lens Zooms come in various focal length ranges, such as 35 to 105mm; all focal lengths including and within this range can be utilized
zoom lens: Lenses that are capable of changing their focal length in real time This is an extraordinarily complicated optical trick and most consumer lenses do a poor job of it Until you have eaten enough ramen noodles to afford a professional zoom lenses (usually those > $1000), stick with fixed focal length lenses
zoom lens: A zoom lens offers a continuously variable focal length, normally without the need to refocus A wide-angle zoom usually covers a range of focal lengths that offer a wide angle A standard zoom goes from a slight wide angle to telephoto and a telezoom covers a range of telephoto focal lengths Some zoom lenses are called super zooms because they cover a larger range of focal lengths from wide angle to longer telephoto Most compact and digital cameras come with some form of standard zoom When the lens is a zoom variety we've give the zoom ratio A 3x zoom doesn't necessarily mean that it will magnify the subject by 3x it's the magnification range from one extreme to the other
zoom lens: A lens in which the focal length can be adjusted over a wider range, giving the photographer, in effect, lenses of many focal lengths
zoom lens: A lens system that allows variable magnification capability
zoom lens: Some electronic projectors come with zoom lenses and some don't This feature allows the user to place the projector in a fixed location and alter the projected image size by simply turning the zoom lense and then focusing the final image Small ultra-portable projectors may not have this feature You will need to determine if physically moving the projector closer or farther from the screen (for a non-zoom lens product) is a challenge to how you set-up your presentations and purchase accordingly
zoom lens: Lens that is constructed to allow continuously variable focal length within a specific range