How do the different kinds of lenses work?
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Lens (optics)\nFrom Wikipedia, the free encyclopedia\nJump to: navigation, search\n\n    This article is about the optical device. For other senses of this word, see lens.\n\nA lens.\nEnlarge\nA lens.\n\nA lens is a device for either concentrating or diverging light, usually formed from a piece of shaped glass. Analogous devices used with other types of electromagnetic radiation are also called lenses: for instance, a microwave lens can be made from paraffin wax.\nContents\n[hide]\n\n    * 1 History\n    * 2 Lens construction\n          o 2.1 Sign convention of lens radii R1 and R2\n          o 2.2 Types of lenses\n          o 2.3 Lensmaker's equation\n                + 2.3.1 Thin lens equation\n    * 3 Imaging properties\n    * 4 Aberrations\n          o 4.1 Spherical aberration\n          o 4.2 Coma\n          o 4.3 Chromatic aberration\n          o 4.4 Aperture Diffraction\n    * 5 Multiple lenses\n    * 6 Uses of lenses\n    * 7 See also\n    * 8 References\n          o 8.1 General\n          o 8.2 Footnotes\n    * 9 External links\n\n[edit]\n\nHistory\n\nThe earliest written records of lenses date to Ancient Greece, with Aristophanes' play The Clouds (424 BC) mentioning a burning-glass (a convex lens used to focus the sun's rays to produce fire). The writings of Pliny the Elder (23–79) also show that burning-glasses were known to the Roman Empire[1], and mentions what is possibly the first use of a corrective lens: Nero was known to watch the gladiatorial games using an emerald[2] (presumably concave-shaped to correct for myopia, though the reference is vague). Both Pliny and Seneca the Younger (3 BC–65) described the magnifying effect of a glass globe filled with water. The Arabian mathematician Ibn Sahl (c.940–c.1000) used what is now known as Snell's law to calculate the shape of lenses[3], and Alhazen (Abu Ali al-Hasan Ibn Al-Haitham) (965–1038) wrote the first major optical treatise which described how the lens in the human eye formed an image on the retina. The oldest lens-artefact however is dated to 640s BC; a rock crystal lens found at excavations in Ninive.\n\nRecent excavations at the Viking harbor town of Fröjel, Gotland in Sweden have revealed rock crystal lenses produced at Fröjel in the 11th to 12th century via turning on pole-lathes have been found that have an imaging quality comparable to that of 1950's aspheric lenses. The Viking lenses quite effectively concentrate sunlight enough to ignite fires.\n\nWidespread use of lenses did not occur until the invention of spectacles, probably in Italy in the 1280s.\n[edit]\n\nLens construction\n\nThe most common type of lenses are spherical lenses, which are formed from surfaces that have spherical curvature, that is, the front and back surfaces of the lens can be imagined to be part of the surface of two spheres of given radii, R1 and R2, which are called the radius of curvature of each surface.\n[edit]\n\nSign convention of lens radii R1 and R2\n\nThe signs of the lens radii indicate whether the corresponding surfaces are convex (bulging outwards from the lens) or concave (depressed into the lens). The sign convention used to represent this varies, but in this article if R1 is positive, the first surface is convex, and if R1 is negative, the surface is concave . If R1 is infinite, the surface is flat, or has zero curvature, and is said to be planar. The signs are reversed for the back surface of the lens: if R2 is positive, the surface is concave, and if R2 is negative,the surface is convex.\n[edit]\n\nTypes of lenses\nBiconcave Lens\nEnlarge\nBiconcave Lens\nPlano-convex Lens\nEnlarge\nPlano-convex Lens\n\nThe line joining the centres of the spheres making up the lens surfaces is called the axis of the lens; in almost all cases the lens axis passes through the physical centre of the lens.\n\nLenses are classified by the curvature of these two surfaces. A lens is biconvex (or just convex) if both surfaces are convex, likewise, a le
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a regular camera lens focuses in light sensitive diodes, then the diodes changes electricity into digital elericity which is  0s and 1s which can be a file on a computer, and then those can focus on the computer into a folder
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Focal length.\nThe distance from the lens to a point at which the light going through the lens will converge into a sigle point.\n\nAfter the light enters a lens straight on, the light is bent, causing the light to focus toward a signle point. After that point the image is turned upside down.
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It focuses an image on the retina so that you can see it.  The shape of the lens in the eye is controlled by muscles, so that the focal length can be adjusted to get sharp focus of both near and distant objects.  Errors in the shape of the lens can be corrected with eyeglasses.
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Really interesting question. \n\nThe Abbe Sine Condition is explained simply and clearly online, see the link below. \n\nBasically it is a simple mathematical formula which predicts how to make lenses form a sharp, good quality image. It simply relates the angles of two kinds of light ray and helps in lens design.\n\nThe two kinds of light rays he talks about are rays beaming in close to the center line and rays starting at the center line and beaming outwards to the outer edges of the aperture (opening) of the lens.\n\nThese two types of rays are called paraxial (because they are almost PARAllel to the AXIs) and marginal rays (because they head towards the MARGIN or edge of the lens opening). \n\nThese simple equations are still used today in Computer Graphics for tracing the paths of light rays and producing realistic effects.\n\nAbbe was a cool guy, he was one of the first managers to insist on an eight hour day for his workers.
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In short, the diaphrgm controls the size of the opening which lets the light through the lens.  The larger the diameter, the more light comes in, so that one would use a wider opening on a darker day.\n\n(Just to confuse you, you should know that the larger the number on the diaphragm, the smaller is the diameter.)
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Focal length is the distance it takes a lens to focus an image onto a surface, especially within a camera. Depth of field is how much of your image is within the precise area of focus, here we are talking about a, "front" to "back" effect, which is why it is "depth" of field. Focal length is fixed, depth of field is variable. \nDepth of field is controlled by use of "f" stops. As an example, a lens set to f1.8 has a shallower depth of field than a lens set to f13.
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_______I_____I_____()_____I__________________\n              o          f                      f \nas the law of convex lense is that is a ray is passing from optical center<that is the mid of the convex lens >then there will be no change in its direction and if another ray is paralell to principal axis <that is the long straight line>then the ray will pass from principle focus<that is f>then keep on drawing the rays until they converge together at a point that will be ur image ......after taht u can use the formula to calculate it or just measure the distances\n1/image distance+1/object distance=1/focal length\nu can change it to\n1/image distance=1/focal length-1/object distance\n                            =1/3-1/5\n                                   5-3\n                             =_____________\n                                   15\n                             =2\n                               __________\n                                   15\n now we will flip it to\n      15\n_________\n        2\nand then we will get 7.5 answer\ni hopedi helped u i m studying this too right now in 0 levels i have a lot of h.w about it today
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If you're talking about a lens in the shape of a contact: distortion or "pincushioning" of the center of your field of vision. It increases the peripheral range somwhat.\n\nif youre talking about with a microscope: severe limitation of view range, and the item you are focusing on has much sharper focus, and you can see details of its surface...
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A parfocal is a type of lens, used in some microscopes.  The basic idea is, as you change objectives (and thus, magnification) the image should pretty much stay in focus.  In most microscopes, changing the magnification means you have to re-focus.  Parfocals are a convenient solution.
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It's called simultaneous viewing.  You actually look through the distance, near, and intermediate portions of the lens at the same time (they're each determined by a different curve on the lens).  Your brain automatically selects the clearest image.
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the magnifying of the lens: M = 4 and by definition \nM = -di/do\ndo is the distance from lens to object\ndi is the distance from lens to image\nso -di/do = 4 ---> di = -4do\nthe thin lenses equation:\n1/f = 1/do + 1/di\n1/f = 1/do + 1/(-4do)\n1/f = 1/do - 1/(4do) = 3/(4do)\nf = 4do/3 = (4*2.88 cm)/3\nf = 3.84 cm
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Through the cornea and then through the lens.\nMost of the refraction is due to the cornea
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The same reason why a pinhole camera works.  As light passes therough the pinhole, it refracts and is focused.
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In a refracting telescope, light is focused using a series of lenses. In a reflecting telescope, it is focused using curved mirrors.
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Yes - to protect your eyes from the sun's harmful rays.  As for looking for good ones - beyond style and fit - make sure the lenses have max UV protection.  Talk to someone in an optical department about it.  UV A and UV B protection is what you want to have.
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Magnifying mirrors are concaved inward and work by focusing the light on a point such that the image is larger than the original object.\n\nhttp://physics.bu.edu/py106/notes/Spherical.html