How Do You Make A Camera Lens

Photographic camera Lens

Background

The camera lens is an invention that attempts to indistinguishable the functioning of the human eye. But like the eye, the lens sees an paradigm, focuses information technology, and transmits its colors, sharpness, and effulgence through the photographic camera to the photographic film, which, like our memory, records the image for processing and future use. Lenses are made of optical glass or plastic. They focus light rays by refracting or bending them so that they meet or converge at a common point.

A uncomplicated lens "sees" well through its center, but its vision around the edges tends to blur. Blurring, color changes, baloney of lines, and colour halos around objects are caused by defects in the lens called aberrations. Some aberrations tin be corrected in the uncomplicated lens by shaping i or both surfaces so they are aspheric; aspheric curves vary like the curves of a parabola, rather than staying constant like the curvature of a sphere. A camera lens reduces the effects of aberrations by replacing a simple lens with a grouping of lenses called lens elements, which are lenses of dissimilar shapes and distances of separation. The lens becomes more complex as greater correction of vision is accomplished. The lens will also exist more complex depending on the size of the discontinuity—the opening that allows light to pass through—and the range of angles it "sees." Lens design used to rely on the optician's art and considerable experimentation. Today, computer programs can adapt the shaping and spacing of lens elements, make up one's mind their effects on each other, and evaluate costs of lens production.

Lens elements are usually described by their shape. The convex lens curves outward; a biconvex lens curves outward on both sides, and a plano-convex lens is apartment on one side and outwardly curved on the other. At that place are besides concave lenes, biconcave, and plano-concave lenses. The elements are not necessarily symmetrical and can curve more on one side than the other. Thickening the middle of the lens relative to its edges causes calorie-free rays to converge or focus. Lenses with thick edges and sparse middles make light rays disperse. A complex camera lens contains a number of elements specially grouped. The combination of the composition, shape, and group of the elements maximizes the lite-bending backdrop of the private elements to produce the desired image. The lens is focused by moving it nearer or further from the film or focal plane. The lens can be twisted, causing the lens elements to move in and out along a spiral screw thread machined into the casing of the lens. Twisting the lens also moves a scale on the casing that shows the distance of the best focus.

The finish or diaphragm is a specialized part of the lens. In simple cameras, the stop is a fixed stop or a ring of black canvas metal that is permanently fix in front end of the lens. Box cameras, studio cameras, and some cameras of European manufacture use a sliding stop, which is a strip of metal that slides across the front of the lens between grooves. It has two or more holes of different sizes that are the apertures. Lenses with a variable stop have a machined ring on the outside of the lens mount, printed with f-stop numbers. By turning this ring, the diaphragm can be opened or closed. This iris diaphragm works much like the iris of the heart in allowing adjustments for varied light conditions.

The lens in a compact photographic camera is usually a full general-purpose lens with a normnal focal length that takes pictures of an prototype the way our optics see it. Lenses designed for special purposes are used with more than advanced cameras. Telephoto lenses work much like binoculars or telescopes, and make a distant epitome appear closer. Broad-angle lenses make the image appear farther away; a panoramic lens is a special kind of wide-angle lens that is useful for taking pictures of wide expanses of scenery. Some dispensable cameras are equipped with panoramic lenses. A fish-middle lens is likewise a special kind of wide-bending lens that deliberately distorts the prototype and then the central part is enlarged and the outer prototype details are compressed. Fish-heart lenses comprehend very wide angles like horizon-to-horizon views. Another special purpose lens is the variable-focus lens, also chosen a "zoom" lens. It uses moveable lens elements to arrange the focal length to zoom closer to or farther abroad from the subject. These lenses are complex and may incorporate 12 to 20 lens elements; still, one variable-focus lens may replace several other lenses. Some compact cameras also have limited zoom, telephoto, or wide-angle features. The single-lens reflex (SLR) photographic camera is made so that the photographer sees the same view as the lens through the viewfinder. This enables the photographer to programme the image that will announced on moving-picture show with the flexibility of a diverseness of interchangeable lenses.

History

The photographic camera lens evolved from optical lenses developed for other purposes, and matured with the camera and photographic film. In 1568, a Venetian nobleman, Daniel Barbaro, placed a lens over the pigsty in a camera box and studied sharpness of image and focus. His commencement lens was from an old human being's convex spectacles. The astronomer Johann Kepler elaborated on Barbaro's experiments in 1611 by describing single and chemical compound lenses, explaining paradigm reversal, and enlarging images by group convex and concave lenses.

In the 1800s, the start box cameras had a lens mounted in the opening in the box. The lens inverted the image on a light-sensitive plate at the back of the box. In that location was no shutter to open the lens; instead, a lens cap was removed for several seconds or longer to expose the plate. Improvements in the sensitivity of the plate necessitated ways of decision-making the exposure. Masks with unlike sized openings were made for insertion near the lens. The iris diaphragm was also developed to control the aperture. Its metallic leaves open and shut together to grade a circular opening that tin can be varied in diameter.

In 1841, Joseph Petzval of Vienna designed a portrait lens with a fast aperture. Previously, lenses made for daguerreotype cameras were best suited for landscape photography. Petzval'south lens immune portraits to be taken ten times faster, and the photograph was less likely to be blurred. In 1902, Paul Rudolph adult the Zeiss Tessar lens, considered the most pop ever created. In 1918, he produced the Plasmat lens, which may be the finest camera lens ever fabricated. Rudolph was followed shortly by Max Berek, who designed sharp, fast lenses that were ideal for miniature cameras.

Other essential developments in lens history include lens coating technology, use of rare-earth drinking glass, and adding methods fabricated possible by the calculator. Katharine B. Blodgett developed techniques for thin-blanket lenses with lather movie to remove reflection and better light transmission in 1939. C. Hawley Cartwright continued Blodgett'south work by using coatings of metallic fluorides, including evaporated magnesium and calcium that were four-ane-millionths of an inch thick.

Pattern

Blueprint of a photographic camera lens begins by identifying the photographer who will use it. When the marketplace is identified, the lens designer selects the optical and mechanical materials, the optical design, the appropriate method for making the mechanical parts, and, for auto focus lenses, the type of inter-face up between the lens and camera. There are conventions or patterns for the different categories of lenses, including macro, wide-angle, and telephoto lenses, then some pattern aspects are standardized. Advancements in materials give designers many challenging

A group of lenses chosen lens elements, which are of different shapes and distances of separation, make upwards the camera lens. Lens design used to rely on the optician's art and considerable experimentation. Today, computer programs can adjust the shaping and spacing of lens elements, determine their effects on each other, and evaluate costs of lens production.

options, nonetheless. In selecting materials, the engineer must consider a range of metals for the components and diverse types of glasses and plastics for the lenses, all the while mindful of the final cost to the photographer.

When the designer has completed the blueprint, its operation is tested by reckoner simulation. Figurer programs that are specific to lens manufacturers tell the designer what kind of image or picture the lens will produce at the center of the paradigm and at its edges for the range of lens operation. Assuming the lens passes the computer simulation examination, the criteria for performance that were chosen initially are reviewed once more to confirm that the lens meets the needs identified. A epitome is manufactured to test bodily performance. The lens is tested under varying temperature and environmental conditions, at every aperture position, and at every focal length for zoom lenses. Target charts in a laboratory are photographed, as are field conditions of varying light and shadow. Some lenses are anile rapidly in laboratory tests to cheque their durability.

Additional design work is needed if the lens focuses automatically, because the auto focus (AF) module must work with a range of photographic camera bodies. The AF module requires both software and mechanical design. Extensive epitome testing is performed on these lenses considering of their complex functions and because the software is fine-tuned to each lens.

Raw Materials

The raw materials for the lenses themselves, the coating, the barrel, or housing for the camera lens, and lens mounts are described beneath in the manufacturing section.

The Manufacturing
Procedure

Grinding and polishing lens elements

• 1 Optical glass is supplied to lens manufacturers past specialized vendors. Usually, it is provided as a "pressed plate" or sliced glass plate from which the elements are cutting. The drinking glass elements are shaped to concave or convex forms past a curve generator machine that is a first-step grinder. To reach the specifications for its shape, a lens goes through a sequence of processes in which it is ground by polishing particles in h2o. The polishing particles become smaller in each step as the lens is refined. Curve generation and subsequent grinding vary in speed depending on the frailty, softness, and oxidation properties of the optical materials.

  Later grinding and polishing, the elements are centered so that the outer edge of the lens is perfect in circumference relative to the centerline or optical axis of the lens. Lenses made of plastic or bonded glass and resin are produced by the same processes. Bonded materials are used to brand lenses with non-spherical surfaces, and these lenses are called "hybrid aspherics." The aspherical surfaces of these lenses are completed during centering.

Coating lenses

• two Formed lenses are coated to protect the material from oxidation, to preclude reflections, and to come across requirements for "designed spectrum manual" or colour balance and rendition. The lens surfaces are carefully cleaned before blanket. Techniques for applying coatings and the coatings themselves are major selling points for a manufacturer'south lenses and are carefully guarded secrets. Some types of coatings include metallic oxides, light-blend fluorides, and layers of quartz that are applied to lenses and mirrors by a vacuum process. Several layers of blanket may be applied for the best color and calorie-free transmission, but excessive blanket can reduce the light that passes through the lens and limit its usefulness.

Producing the barrel

• 3 The barrel includes the chassis that supports the various lens elements and the corrective exterior. Metal mounts, grooves, and moving portions of the lens are critical to the performance of the lens, and are machined to very specific tolerances. Lens mounts may be made of contumely, aluminum, or plastic. Most metallic butt components are die-bandage and machined. Metal mounts last longer, maintain their dimensions, can exist machined more precisely, and can be dismantled to replace elements, if necessary. Plastic mounts are less expensive and of lighter weight. If the barrel is fabricated of engineering plastic, it is produced by a highly efficient and precise method of injection molding. The interior surfaces of the butt are as well coated to protect them and to preclude internal reflection and flare.

Assembling the lens

• four Other parts of the lens, such as the diaphragm and auto focus module, are produced every bit subassemblies. The iris diaphragm is constructed of curved leaves cut out of thin sheets of metal. The metal leaves are held in place past two plates. One plate is fixed, the other moves, and has slots for sliding pins. These slide the leaves back toward the barrel to open the diaphragm or into the heart to close the opening as the f-stop band is turned. The diaphragm assembly is attached into place when the lens mountain is attached to the end of the barrel. The car focus is also added, the optical elements are positioned, and the lens is sealed. After final assembly, the lens is adjusted and inspected rigorously. It must meet the design standards for optical resolution, mechanical function, and machine focus response. Lenses may also exist tested by subjecting them to shocks, dropping, and vibration.

Quality Control

Approaches to lens manufacture vary greatly among companies. Some utilize full automation including industrial robot s to make their products, others use large assembly lines, and however others pride themselves on paw-crafting. Quality and precision are essential to lens production, however, regardless of manufacturing arroyo. Incoming materials and components are rigorously inspected for quality and compliance with engineering specifications. Automated processes are as well inspected constantly and subjected to tolerance checks. Paw-craftsmanship is performed only by skilled artisans with long years of training. Quality command and stress tests are incorporated in each manufacturing footstep, and elements and components are measured with precise instruments. Some measuring devices are light amplification by stimulated emission of radiation-controlled and can notice deviations of less than 0.0001-millimeter in a lens surface or in lens centering.

The Future

Camera lenses are enjoying new developments in many areas. The consumer'due south interest in the best photos for the everyman cost has led to disposable cameras with simple merely effective lenses. Lenses for professional person photographers and for specialized uses such as high-functioning binoculars or telescopes are fabricated with exotic and "not-preferred" glasses that are more sensitive, expensive, and harder to obtain than traditional materials. These are called "abnormal dispersion" materials because they merge all the colors in the low-cal passing through the lens to produce the all-time images, rather than allowing colors to disperse like a simple lens. H2o and other liquids also bend calorie-free, and scientists have identified liquids that are abnormally dispersive and can be trapped between layers of ordinary glass to produce the same prototype quality equally exotic optical glass. The ordinary or "preferred" drinking glass (preferred considering of depression toll and workability) is bonded around the liquid with flexible silicone agglutinative. The resulting "liquid lens" may supervene upon several elements in a professional-quality lens. Information technology likewise reduces the coating required and the corporeality of lens polishing needed because the liquid fills imperfections in the glass. The cost of the lens is reduced, and the calorie-free transmission properties are improved. Lens makers in the U.Due south., Nihon, and Europe are preparing to produce liquid lenses in the near hereafter.

Where To Learn More

Books

Bailey, Adrian and Adrian Holloway. The Book Of Color Photography. Alfred A. Knopf, 1979.

Collins, Douglas. The Story of Kodak. Harry North. Abrams, Inc., Publishers, 1990.

Sussman, Aaron. The Amateur Photographer's Handbook. Thomas Y. Crowell Company, 1973.

Periodicals

Coy, Peter, ed. "A Clear-Eyed View from Liquid Camera Lenses." Business Week, January 17, 1994, p. 81.

From Drinking glass Plates to Digital Images. Eastman Kodak Company, 1994.

"Photographic Lenses." Photographic, Apr 1991, pp. 56-57.

"Liquid Lens." Popular Science, May 1994, p. 36.

— Gillian South. Holmes

Source: http://www.madehow.com/Volume-2/Camera-Lens.html

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