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Topic: Lens (optics)

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	Lens (optics) - Wikipedia, the free encyclopedia
		If the lens is biconvex or plano-convex, a collimated or parallel beam of light travelling parallel to the lens axis and passing through the lens will be converged (or focused) to a spot on the axis, at a certain distance behind the lens (known as the focal length).
		The beam after passing through the lens appears to be emanating from a particular point on the axis in front of the lens; the distance from this point to the lens is also known as the focal length, although it is negative with respect to the focal length of a converging lens.
		Chromatic aberration is caused by the dispersion of the lens material, the variation of its refractive index n with the wavelength of light.
	en.wikipedia.org /wiki/Lens_(optics) (2603 words)

	LENS (OPTICS) - LoveToKnow Article on LENS (OPTICS) (Site not responding. Last check: 2007-10-22)
		lens, lentil, on account of the similarity of the form of a lens to that of a lentil seed), in optics, an instrument which refracts the luminous rays proceeding from an object in such a manner as to produce an image of the object.
		The most important type of lens is the spherical lens, which is a piece of transparent material bounded by two spherical surfaces, the boundary at the edge being usually cylindrical or conical.
		The values of Si and S2 show that the optical centre of a biconvex or biconcave lens is in the interior of the lens, that in a plano-convex or plano-concave lens it is at the vertex of the curved surface, arid in a concavo-convex lens outside the lens.
	45.1911encyclopedia.org /L/LE/LENS_OPTICS_.htm (6832 words)

	lens, in optics. The Columbia Encyclopedia, Sixth Edition. 2001-05
		The lens of the eye is known as a crystalline lens.
		The distance from the principal focus to the optical center of the lens is the focal length of the lens.
		As the object is brought toward the lens, the size of the image grows, becoming as large as the object when the object is at the center of curvature and larger than the object as the object is brought closer.
	www.bartleby.com /65/le/lens.html (756 words)

	Lens - Wikipedia, the free encyclopedia
		Photographic lens, a special type of lens used in a camera.
		Lens (genus), the genus of the lentil plant
		Lens (geometry), a geometric shape formed from two arcs
	en.wikipedia.org /wiki/Lens (151 words)

	Optical Research Associates - A Gentle Introduction to Optical Design (Site not responding. Last check: 2007-10-22)
		Optics is concerned with all aspects of the behavior of light and thus covers a lot of territory.
		Optics can help us with these other wavelength regions, but most of our discussion here will focus on the important and familiar visible spectrum (i.e., the colors of the rainbow, from violet light with wavelengths near 400 nm [nanometer, one-billionth of a meter] to red light near 700 nm).
		The optics pages discuss a lot of basic optical concepts with a useful approach that is geared toward the importance of these concepts to the actual use of the optics.
	www.opticalres.com /gentle95.html (2987 words)

	Articles - Lens (optics) (Site not responding. Last check: 2007-10-22)
		A lens with one convex and one concave side is termed ´´convex-concave´´, and in this case if both curvatures are equal it is a ´´meniscus´´; lens.
		If the lens is biconvex or plano-convex, a collimated or parallel beam of light travelling parallel to the lens axis and passing through the lens will be converged (or ´´focused´´) to a spot on the axis, at a certain distance behind the lens (known as the ´´focal length´´;).
		´´Chromatic aberration´´; is caused by the dispersion of the lens material, the variation of its refractive index ´´n´´ with the wavelength of light.
	www.newmirror.com /articles/Lens_(optics) (2463 words)

	Lens (optics) at opensource encyclopedia (Site not responding. Last check: 2007-10-22)
		Rays which pass through the centre of the lens of focal length f are focussed at a point with distance f tan θ from the axis.
		Rays passing through the outer margins of the lens are focussed at different points, either further from the axis (positive coma) or closer to the axis (negative coma).
		In general, a bundle of parallel rays passing through the lens at a fixed distance from the centre of the lens are focussed to a ring-shaped image in the focal plane, known as a comatic circle.
	www.wiki.tatet.com /Lens_(optics).html (1784 words)

	Phys 152 - Lens Optics - Spring 2006
		Use a second converging lens with a shorter focal length to examine the image created by the first lens.
		Lens notation: The lenses you will be using are marked with a series number (the last three digits, e.g.
		Using the measured focal length of the 800-series lens, calculate the lens-object distance (o = o'f) and the expected lens-image distance (i = i'f) for each generic object distance given in your table.
	it.stlawu.edu /~physics/labs/152_lab/html/optics.shtml (615 words)

	Lenses \| Blur, Focus, Bokeh, Aperatures and f-Stops.
		The lens projects an image of an object onto a screen by gathering rays "never intended for the screen" and bending them back towards the screen until they arrive in such quantities at the surface of the screen that they "outnumber" the other rays coming from all kinds of other sources.
		Make the lens half as big in area, and half of the rays that were redirected by the lens from Point A to Point B now resume their original paths.
		Because a pinhole camera lens operates with so little light, it cannot allow to pass through itself a quantity of rays sufficient to compete with much ambient light at all, and if it is to project a discernable image onto film, it must operate in a light-tight camera and with relatively long exposure times.
	www.digitalartform.com /lenses.htm (1200 words)

	Lens (optics) - Search Results - MSN Encarta
		Optics, branch of physical science dealing with the propagation and behaviour of light.
		Lens (optics), in optical systems, glass or other transparent substance so shaped that it will refract the light from any object, and form a real or...
		Aperture, in optics, the opening of a lens through which light can enter.
	uk.encarta.msn.com /Lens_(optics).html (126 words)

	IVCam: Rendering with Real-Lens Optics
		As noted in [#!kolb!#], a thick lens approximation is only valid if the lens system distortion is negligible, such that a circular disk is a reasonable approximation from an off-axis point on the film plane, which is not necessarily the case for wide-angle lenses.
		The effective focal length of the lens is then considered the distance between this plane and the image-side focal point F (the front focal length is the distance to the object-side focal point F').
		Real-world and Inventor scenes were photographed using optics with focal lengths of approximately 20 (Figures 7 and 10), 60 (Figures 8 and 11), and 180 millimeters (Figures 9 and 12).
	web.mit.edu /sirkin/www/paper (6187 words)

	Polar Optics Motorcycle Helmet Faceshield Lens - webBikeWorld
		The Polar-Optics lens comes with two long strips of "hook" material, one of which is used to place across the top of your helmet's visor, and the other to be used as a spare in case you make a mistake when you're mounting the lens.
		I assumed that the lens would be long enough so that it wouldn't be in my line of sight, but I wish I had mounted it about, oh, 1/4" farther down, because the bottom of the lens slightly interferes with my vision as it's currently situated.
		The lens is polarized to reduce glare and the lens is optically correct.
	www.webbikeworld.com /r2/polar-optics/polar-optics.htm (2345 words)

	Contact Lens Spectrum
		BY PETER D. he combination of rigid lens optics and soft lens comfort has long been a quest of contact lens technology.
		The SynergEyes lens makes use of the Paragon HDS 100 material for the center, optical portion of the lens, which is available in a standard 8.4mm diameter and radii from 7.10mm to 8.20mm in 0.10mm increments.
		These trials led to the standard recommendation that the central optic should be 0.3mm, or about 1.25D, steeper than flat K. It's imperative that you fit the central optic with central clearance, or the lens will tighten with wear, leading to an immobile, uncomfortable lens.
	www.clspectrum.com /article.aspx?article=12939 (544 words)

	Optical Research Associates - Optics for Kids (Site not responding. Last check: 2007-10-22)
		Optics (optical science) and optical engineering are specialized but very useful and interesting fields, though there are many, many other areas too.
		OSA (Optical Society of America) has a great educational web site that is also called "Optics for Kids." This site has a colorful, graphics-rich interface and provides many fun and educational features including articles, experiments, and lesson plans (http://www.opticsforkids.org/teach/teach.cfm) arranged by grade level.
		The "What is Optics?" (http://www.opticsforkids.org/what/what.cfm) section covers many of the subjects discussed here, but in greater detail.
	www.opticalres.com /kidoptx.html (2346 words)

	Optics pages
		Spherical aberration occurs when the lens margins focus the light closer to -or further from- the sensor than the lens center.
		Astigmatism implies that a lens can be sharper in one direction than another.
		Photographers who notice color fringing in their retrofocus wideangle pictures may decide to stop the lens down further, but to no effect: lateral color is not cured by a small aperture size.
	www.vanwalree.com /optics.html (515 words)

	Optics
		The NORMAL is a line of reference that is perpendicular to the surface of the optic at the point of reference.
		Because the plane Waves are orthogonal to the angle of incidence, upon exiting from the Plano surface of the lens, the Plane Waves remain unchanged; that is they project an image of source S as parallel waves (neither diverging or converging)..
		Because the plane Waves are orthogonal to the angle of incidence (90º), upon exiting from the Plano surface of the lens, the Plane Waves remain unchanged; that is they project an image of source S as parallel waves (neither diverging or converging)..
	www.williamson-labs.com /optical-body.htm (2062 words)

	Simulated Optics Experiments: Single Lens - Succeed in Physical Science
		A convex lens is one in which the center is wider than the ends.
		A concave lens has the center "caved in" and is wider at the edges.
		A concave lens is wider at the edges than at the middle.
	www.school-for-champions.com /science/experiments/simopticslens.htm (1330 words)

	Technology: L-Series Lenses
		Aspherical optics, which have an extremely precise variable curvature of one or both sides of a lens element, also allow more compact lens designs and permit lighter lenses with fewer elements.
		Many EF telephoto lenses are white, to reduce the amount of internal heat build-up during long shooting in bright sunlight.
		Their superb optics enable pros and advanced amateurs to have lenses that are the absolute pinnacle of optical performance, and enable lens/speed combinations with professional performance simply not attainable using traditional optical technology.
	opd.usa.canon.com /html/eflenses/technology/lseries.html (288 words)

	Optics Bench
		You should notice when the applet loads that the screen area is fl with a yellow horizontal line dividing the dark area into two equal halves.
		This area is the optics bench active area.
		The yellow line is the principal axis for any lens or mirror in the active area.
	www.hazelwood.k12.mo.us /~grichert/optics/intro.html (557 words)

	Metro-Optics : Contact Lenses that Deliver
		In short, Metro Optics is your one-stop shop for all the contact lens needs of a contemporary eye care practice.
		Our lens designs reflect the experience and attention to detail that has characterized the Metro Optics approach since first opening in 1973.
		Metro Optics founders believe that an excellent product, good customer relations and attention to design are the cornerstones of every successful business.
	www.metro-optics.com (318 words)

	Lens (optics) Life history @ NaturalResearch.org (Natural Research) (Site not responding. Last check: 2007-10-22)
		Lens (optics) Life history @ NaturalResearch.org (Natural Research)
		The Viking lenses quite effectively concentrate sunlight enough to ignite fires.
		The simplest case is when lenses are placed in contact: if the lenses of focal lengths f
	www.naturalresearch.org /encyclopedia/Lens_(optics) (1673 words)

	OAKLEY - HALF JACKET - SUNGLASSES
		Choose between two unique lens shapes: the Standard Lens and the larger XLJ Lens.
		Metallic oxides are superheated to 1500 degrees Celsius and fused to the lens at the molecular level, permanently bonding to create a uniform filtering layer that optimizes contrast and minimizes glare.
		Holding the lens firmly, slide your thumb across the top of the frame until the inner lens tab snaps into the groove in the nose bridge.
	oakley.ca /brochures/eyewear/half_jacket (375 words)

	American Science & Surplus: Optics - Lenses and Lens Cleaners
		Brand new, for a projection TV, this 4-element lens is in a 6-1/8" long x 5-1/4" dia fl steel barrel with #24 threads at both ends and has what looks to be approx 16" to 17" focal length.
		As you move the coated lens away from your eye the image will stay in perfect focus from up close to about the 7-7-1/2" nominal focal length.
		If there is a particular lens that might fulfill a production requirement, we would be pleased to provide information on total availability and larger quantity pricing.
	www.sciplus.com /category.cfm?subsection=21 (486 words)

	COOKEOPTICS.COM - Cooke Optics, Video Lenses, Large Format, S4/i, CXX zoom, Cine Lens, motion picture, large format ...
		Cooke 12mm S4/i lens -- the latest addition to the Cooke S4/i Prime lens focal lengths.
		lens for 4x5 large format photography are available for order through our
		Photographer Don Tsusaki, is forming a user group exclusively for owners of the Cooke PS945 lens for sharing information, tips and techniques.
	www.cookeoptics.com (318 words)

	Smith Optics \| Press Release \| Smith introduces Golf Tint Interchangeable Lens (Site not responding. Last check: 2007-10-22)
		The replacement lens will be available for all current Smith Optics Interchangeable sunglasses, and will be available installed and ready-for-purchase in five current models.
		The new gray-copper based performance lens tint was created to maximize definition and clarity of the ball against the grass, and helps in reading the greens by highlighting shadows and undulations in the green surface.
		From Smith’s distortion-free Tapered Lens Technology to the versatility of the Slider Series, with its patented, interchangeable lens system, the devotion to excellence, innovation and style is what has made Smith goggles and sunglasses the choice of action-sport athletes worldwide.
	www.smithsport.com /news/pressrelease_0605_golftintintro.html (325 words)

	Digital Optics .45X WIDE ANGLE LENS {28MM}
		The Titanium Digital Optics multi-coated.45X lens for 28mm diameter is a professional grade, wide-angle converter that increases the angle of view by 100%, allowing the video or digital camera to take breathtaking ultra wide-angle shots.
		The lens attaches easily and directly to any camera or camcorder with a 28mm filter thread.
		Macro:The Macro mode is accomplished by unscrewing the front lens assembly and using the section labeled Macro with your existing camera lens.
	www.buydig.com /shop/product.aspx?sku=sakdowa28 (224 words)

	NTNU JAVA :: View topic - Thin Lens (converging/diverging lens/mirrors) (Site not responding. Last check: 2007-10-22)
		I attend the university of wisconsin-madison and I was having problems with optics concepts.
		I went under the internet and searched under lens and mirrors and fell upon your lab.
		I was looking at your applet for the thin lens and really liked it.
	www.phy.ntnu.edu.tw /java/Lens/lens_e.html (1543 words)

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