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  • WordNet 3.6
    • n lens a transparent optical device used to converge or diverge transmitted light and to form images
    • n lens electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons
    • n lens biconvex transparent body situated behind the iris in the eye; its role (along with the cornea) is to focuses light on the retina
    • n lens (metaphor) a channel through which something can be seen or understood "the writer is the lens through which history can be seen"
    • n Lens genus of small erect or climbing herbs with pinnate leaves and small inconspicuous white flowers and small flattened pods: lentils
    • ***

Additional illustrations & photos:

Large lens Large lens
Front view of lens Front view of lens
Focussing Action of Lens Focussing Action of Lens
Achromatic Lens Achromatic Lens

Webster's Revised Unabridged Dictionary
  • Interesting fact: Benjamin Franklin had poor vision and needed glasses to read. He got tired of constantly taking them off and putting them back on, so he decided to figure out a way to make his glasses let him see both near and far. He had two pairs of spectacles cut in half and put half of each lens in a single frame. Today, we call them bifocals.
    • n Lens lĕnz (Opt) 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. In practice, the curved surfaces are usually spherical, though rarely cylindrical, or of some other figure.☞ Of spherical lenses, there are six varieties, as shown in section in the figures herewith given: viz., a plano-concave; b double-concave; c plano-convex; d double-convex; e converging concavo-convex, or converging meniscus; f diverging concavo-convex, or diverging meniscus.
    • ***
Century Dictionary and Cyclopedia
  • Interesting fact: The Chinese invented eyeglasses. Marco Polo reported seeing many pairs worn by the Chinese as early as 1275, 500 years before lens grinding became an art in the West.
    • n lens A piece of transparent substance bounded by two curved surfaces (usually spherical), or by a curved surface and a plane. The ordinary use of a lens is to cause pencils of rays to converge or diverge systematically after passing through it. Lenses for optical purposes are usually made of glass; acoustic lenses, of carbon dioxid inclosed between two thin membranes; lenses for action upon electrical radiations, of paraffin or pitch, substances which are transparent to electrical rays, though opaque to light. Optical lenses alone are in common use. Ordinary lenses are distinguished into two classes—convex or magnifying lenses, which are thickest in the center, and concave, which are thinnest in the center. Each class has three varieties, as shown in fig. 1. To the first belong D, the double-convex or biconvex; C, the plano-convex; and E, the meniscus. The concave lenses are B, the double-concave or biconcave; A, the plano-concave; and F, the concavo-convex, sometimes improperly called concave meniscus. The line which passes through the centers of curvature of the two surfaces is the axis of the lens, and a point on this axis so taken that every line drawn through it pierces parallel elements of the two surfaces is its optical center. A convex lens converges rays which are parallel to its axis, approximately to a point called its principal focus (F in fig. 2). The distance from the optical center to this focus is the same on both sides of the lens, and depends upon the radii of its curved surfaces and the material of which it is made. Rays diverging from a point beyond the principal focus F on either side of the lens are approximately collected to a “real” focus beyond the principal focus on the other side (see fig. 3); but if the source of light is between the lens and its principal focus, the rays after emergence diverge as if they came from a so-called virtual focus behind the luminous point. The luminous point and its focus are interchangeable, and are called conjugate foci, as, for instance, L. and 1 in fig. 3. (See focus, 1.) A concave lens always renders still more divergent rays emanating from a point, and so forms only virtual foci. If the source of light is an extended surface, then the pencil of rays emanating from each point forms its own focus; and the collection of foci constitutes an image, which is real and inverted if the foci are real, but virtual and erect if they are virtual. The relative sizes of the object and image are sensibly proportional, if the lens is thin, to their respective distances from the optical center; if the lens is thick, the distances must be reckoned from the two so-called principal points of the lens (see principal point, under point), which lie on the axis on each side of the optical center. An image formed by a single lens is never perfectly distinct, on account of the spherical and chromatic aberrations of the lens. (See aberration, 4.) The former is due to the fact that a lens bounded by spherical surfaces converges marginal rays to a point nearer the lens than that in which the central rays meet; the latter, to the fact that rays of different color form thoir foci at different distances, the focal distance for violet rays being (with a glass lens) nearly a seventh part shorter than that for the red rays. The spherical aberration can be corrected by making the surfaces of forms other than spherical, or by combining two or more lenses properly proportioned; the chromatic aberration, only by combining two or more convex and concave lenses of different materials, usually a convex of crown-glass with a concave of flint-glass.
    • n lens In anatomy, in the eye, a double-convex body placed in the axis of vision behind the iris between the aqueous humor and the vitreous humor, serving to focus rays of light upon the retina; the crystalline lens. See first cut under eye.
    • n lens Figuratively, photography, from the use of lenses in that art.
    • n lens A genus of leguminous plants of the tribe Vicieæ. It is distinguished from Vicia by having but two ovules instead of many, as is generally the case in Vicia. The 8 species enumerated by some are generally reduced to 2, which are low erector half-climbing herbs with pinnate leaves and small single or racemose pale-blue flowers, natives of the Mediterranean region and eastern Asia. One species, Lens esculenta, the seeds of which are called lentils, is probably one of the oldest of plants cultivated by man for food. See lentil.
    • n lens A genus of dicotyledonous plants of the family Mimosaceæ. There are about 14 species, of which the best-known is L. phaseoloides, the match-box bean or simitar-pod. See Entada, gogo, sea-bean, 1, and simitar-pod.
    • n lens In entomology: The crystalline lens or cone.
    • n lens One of the facets of the compound eye.
    • n lens In geology, a body of ore having a lenticular shape. This type is specially common in metamorphic rocks, such as schists or slates, and is very freqnent with magnetic and specular iron ores, pyrites, and some gold-quartz veins. Lenses of magnetite or pyrites often overlap like shingles.
    • n lens A surface-condenser made of two round, dished plates bolted together, resembling in form a double-convex lens.
    • ***
Chambers's Twentieth Century Dictionary
    • n Lens lenz (optics) a piece of transparent substance with one or both sides convex or concave, the object to refract rays of light really or apparently radiating from a point, and make them deviate so as to pass, or travel on as if they had passed, through another point: the crystalline humour of the eye: a genus of leguminous plants
    • ***


  • Daniel J. Boorstin
    “The traditional novel form continues to enlarge our experience in those very areas where the wide-angle lens and the Cinema screen tend to narrow it.”
  • Debra Winger
    Debra Winger
    “I have a thing with the camera. The lens is unconditional. It doesn't judge you.”
  • Andy Garcia
    Andy Garcia
    “They say a lot of women would like to see me naked, but there's not a lens long enough for that.”


Webster's Revised Unabridged Dictionary
L. lens, a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. Lentil
Chambers's Twentieth Century Dictionary
L. lens, lentis, the lentil.


In literature:

This must be big enough for the camera lens to protrude through.
"The Science of Fingerprints" by Federal Bureau of Investigation
He wins by five len'ths 'n' busts the track record fur the distance a quarter of a second.
"Blister Jones" by John Taintor Foote
He even stuck a louse on the lens and located the beast in the heavens, for the benefit of a doubting Cardinal.
"Little Journeys to the Homes of the Great - Volume 12" by Elbert Hubbard
Name was Len-Len-Len-Leonard Prince.
"The She Boss" by Arthur Preston Hankins
Now, you must think of the eye as a lens, but one made up of cells, of tissues.
"The Sagebrusher" by Emerson Hough
A plank road was constructed to connect the Bethune-Arras road with the Lens-Arras road further forward.
"The Great War As I Saw It" by Frederick George Scott
Len, dear, it was dreadful.
"Four Days" by Hetty Hemenway
I believe if a lens is made as thin as it safely can be, it will be quicker than a thicker one.
"Notes and Queries, Number 188, June 4, 1853" by Various
Our system, in fact, is shaped something like a lens, and our sun is situated near the centre of this lens.
"The Outline of Science, Vol. 1 (of 4)" by J. Arthur Thomson
I never in my life give Len a mite o' news he couldn't ha' picked up for himself.
"Tiverton Tales" by Alice Brown
I looked for tell-tales, and found a television lens set above the door of the room eight feet outside of my steel barrier.
"Highways in Hiding" by George Oliver Smith
The town of Lievin lay astride the Souchez river, about three miles West of Lens.
"The Sherwood Foresters in the Great War 1914 - 1919" by W.C.C. Weetman
Beyond that is a lux metal lens.
"Islands of Space" by John W Campbell
How big a lens did you make, anyway?
"Skylark Three" by Edward Elmer Smith
They are obtained from seeds; the latter being quite small, flat, and lens-shaped.
"The Field and Garden Vegetables of America" by Fearing Burr
Len, can't you spare us a little time?
"The Grammar School Boys of Gridley" by H. Irving Hancock
It struck the searchlight fairly upon the lens.
"Boy Scouts in the North Sea" by G. Harvey Ralphson
One went with the wreck, and this one Len Lewis held on to.
"The Motor Girls on Crystal Bay" by Margaret Penrose
Instinctively, she knew that Len Christie was genuine.
"The Gold Girl" by James B. Hendryx
But Taylor slipped his arm in Len's and drew him aside.
"That Scholarship Boy" by Emma Leslie

In poetry:

Upon my mind
Turn thy pure lens;
Naught shalt thou find
Thou canst not cleanse.
"Confessional" by Paul Laurence Dunbar
Boven ons wijken de wolken weg,
Zeilen de zon voorbij.
Keert ons nog heden het oud beleg,
Toch worden we morgen vrij.
Toch zullen we morgen ontbonden staan
En ver boven 't kleine de vleug'len slaan!
"Ontwaking" by Margot Vos
Yet 'mid these sun—confronting peaks,
The undesisting spirit seeks
To mount to loftier, rarer height.
Are what we see but toys of sense,
And we who see them but a lens
Refracting heavenly light?—
"Celestial Heights" by Alfred Austin
"An' here a-geän's another pleäce,
Where she do zit wi' smilèn feäce,
An' while her bwoy do leän, wi' pride,
Ageän her lap, below her zide,
Her vinger tip do leäd his look
To zome good words o' God's own book.
"The Leädy’s Tower" by William Barnes
A picnic life; from love to love,
From faith to faith they lightly move,
And yet, hard-eyed philosopher,
The flightiest maid that ever hovered To me your thought-webs fine discovered,
No lens to see them through like her.
"The Nomades" by James Russell Lowell
Do you see them there—as long, long since—
Through the lens of History;
Do you see them there as their chieftain prints
In the snow his bended knee,
And lifts his voice through the wintry blast
In thanks for a peaceful home at last?
"Liberty" by James Whitcomb Riley

In news:

Paul Weeks, Todd Borchardt and Len Marano join turnstile and security door firm.
There is one drop of snow that hit the camera lens that made a "moon" appear in the picture.
Book about Len Berg's is on the table.
New Technology at Ferrum College is giving students a look through a different lens.
Len Casteel welcomes Ellen and Tim Fleming to his home where he and Patty Casteel entertained at a party.
It's no surprise to rancher Len McIrvin that a wolf pack preyed on his cattle.
ANAHEIM, Calif, March 24, 2001 — In the history of Maryland basketball, there have been players such as Len Elmore, John Lucas, Tom McMillen, Joe Smith and Steve Francis.
Lens enhances vision without sacrificing comfort.
Combination glasses/lens researched and studied in detail More.
'Half the Sky: Turning Oppression into Opportunity for Women Worldwide' is airing as part of public TV's 'Independent Lens' series.
It will operate as both a 200-400mm or a 280-560mm lens.
Great Smoky Mountains National Park biologist Glenn Taylor uses a hand lens to search for the spruce- fir moss spider on Mount Love along the Appalachian Trail earlier this month.
IN EFFECT UNTIL SEP 6, 5:00 a.m. Cousins Stanley, left, and Len Harris warm up during a short drill at the beginning of practice Wedenesday afternoon at St Lucie West Centennial High School in St Lucie West.
A few days after first seeing the long-tailed beauties, she returned to the site at the edge of a deserted shopping center with her Nikon D300 and 55-200mm lens.
Thanks to the photo-sharing application Instragram, we can see through the lens of Phoenix photographer Alyssa Aragon.

In science:

The increase is large enough that previous analyses of lens statistics were able to obtain interesting upper limits on ΩΛ even from small lens samples.
Rethinking Lensing and Lambda
Figure 1: The opening of the lens and different regions in the lens.
The Riemann-Hilbert approach to double scaling limit of random matrix eigenvalues near the "birth of a cut" transition
Unlike the Laue lens described in Ref. 14, the PM developed is made of crystal tiles rigidly fixed to the lens frame, without any mechanism for adjustment of their orientation in the lens, thus their correct positioning in the lens is performed during the lens assembly.
Focusing of gamma-rays with Laue lenses: first results
Also the effect of the temperature on the focusing properties of the lens have been investigated, finding a significant defocusing when the environment temperature has been decreased by 6 degrees with respect to the mean value (25.5 ◦C) at which the lens assembly procedure was performed.
Focusing of gamma-rays with Laue lenses: first results
By shielding all the lens cystals but one, we have investigated the contribution of each lens crystal to the lens PSF and to the reflected photon spectrum.
Focusing of gamma-rays with Laue lenses: first results
The 40 mW pump laser was focused at the BBO crystal using a f = 300 mm lens. A pair of 10 nm full-width half-maximum (FWHM) interference filters (IF) are used to cut the unwanted pump wavelength noise and the signal/idler photons are coupled to a single-mode optical fiber using a ×10 ob jective lens.
Quantum Random Number Generator using Photon-Number Path Entanglement
We consider the weak de flection limit, where the source and the observer lie in remote regions very far from the lens and photons pass by the lens center at a minimum distance which is much larger than the gravitational radius, i.e. m/b ≡ ǫm ≪ 1.
The role of Lambda in the cosmological lens equation
The associated reference spacetime without the lens is crucial in writing the lens equation, since distances as well as source position β are de fined there .
The role of Lambda in the cosmological lens equation
This contribution is related to the distance from the vacuole boundary to the lens center and do not spring from coupling effects so that it should be incorporated in the total distance Dd from the observer to the lens.
The role of Lambda in the cosmological lens equation
Back-reaction with the lens can however brings about a correction to the de flection near the lens.
The role of Lambda in the cosmological lens equation
The lens equation is derived by fi rst considering geodesic motion of photons in the rest-frame Schwarzschild spacetime of the lens, and, then, light-ray detection in the moving observer’s frame.
On aberration in gravitational lensing
The transverse motion of the observer breaks the circular symmetry for images in the lens plane, but the spherical symmetry of the lens still shows up in the source plane.
On aberration in gravitational lensing
The lens equation written in terms of distances and angles relative to the frame of the moving observer takes the same formal expression as the classic lens equation for a static observer, as already pointed out in Frittelli et al., which considered the opposite point of view of a moving lens and a static observer.
On aberration in gravitational lensing
The first one consider the velocity of the lens at the time the photon passes by the lens [3, 4, 8], the second one refers to the velocity of the observer at the photon reception.
On aberration in gravitational lensing
Therefore, there is no difference between the observations made by a moving observer on a static lens spacetime or a static observer in a moving lens spacetime.
On aberration in gravitational lensing