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43-613: R-D1 was jointly developed by Seiko Epson and Cosina and manufactured by the latter, which also builds the current Voigtländer cameras. It uses Leica M-mount lenses or earlier Leica screw mount lenses with an adapter. An unusual feature to note on the R-D1 is that it is a digital camera that has a manually wound shutter with a rapid wind lever. The controls operate in the same way as film-based rangefinder cameras. Data such as white balance, shutter speed, picture quality, and shots remaining are all displayed with servo driven indicators on

86-431: A decisive role in the manufacturing of aspherical lenses. Depending on the manufacturing process and processing status, various measurement tasks are distinguished: A distinction is made between tactile, i.e. touching, and non-contact measurement methods. The decision as to which method is used depends on accuracy but also on manufacturing state. Tactile measurement is mainly used between two grinding operations to control

129-464: A dial like a watch face (made by Epson's parent company Seiko). With the rear screen folded away, it is not obviously a digital camera. R-D1 and all of the subsequent modifications of the camera have been using the same 1.5x crop factor sensor, interline-transfer CCD ( Sony ICX413AQ ). The same sensor as used in Pentax *ist D , Nikon D100 . Sensor originally dates to 2002. The successor of R-D1 ,

172-474: A much more complex multi-lens system. The resulting device is smaller and lighter, and sometimes cheaper than the multi-lens design. Aspheric elements are used in the design of multi-element wide-angle and fast normal lenses to reduce aberrations. They are also used in combination with reflective elements ( catadioptric systems ) such as the aspherical Schmidt corrector plate used in the Schmidt cameras and

215-447: A prosthetic is customized for an individual. The range of lens powers available to dispensing opticians for filling prescriptions, even in an aspheric form, is limited practically by the size of the image formed on the retina . High minus lenses cause an image so small that shape and form aren't discernible, generally at about −15 diopters , while high plus lenses cause a tunnel of imagery so large that objects appear to pop in and out of

258-409: A reduced field of view, generally at about +15 diopters. In prescriptions for both farsightedness and nearsightedness , the lens curve flattens toward the edge of the glass, except for progressive reading adds for presbyopia , where seamless vari-focal portions change toward a progressively more plus diopter . High minus aspheres for myopes do not necessarily need progressive add portions, because

301-409: A reference beam with the beam reflected from the surface to be measured, error maps, known as interferograms, are created which represent a full-field deviation of the surface shape. Computer-generated holograms (CGHs) represent a method for the interferometric determination of the deviation of the lens from the nominal geometry. These generate an aspherical wavefront in the target shape and thus enable

344-409: A source. Refractive and reflective optical properties can be tabulated as a function of wavelength, to approximate system performances; tolerances and errors can also be evaluated. In addition to focal integrity, aspheric lens systems can be tested for aberrations before being deployed. The use of interferometers has become a standard method of testing optical surfaces. Typical interferometer testing

387-504: A spherical lens to form a composite lens of aspherical shape. Plasma ablation has also been proposed. The non-spherical curvature of an aspheric lens can also be created by blending from a spherical into an aspherical curvature by grinding the curvatures off-axis. Dual rotating axis grinding can be used for high index glass that isn't easily spin molded, as the CR-39 resin lens is. Techniques such as laser ablation can also be used to modify

430-479: A variety of SLR manufacturers' lens mounts. In 1991, it started to produce glass molded aspheric lenses , and in 1996 plastic molded aspherical lenses. Cosina began producing digital cameras in 1997. At about this time, plans were started to produce a new high-quality rangefinder 35 mm film camera, complete with wide and ultrawide lenses for the Leica screw mount , and also a standard 35 mm film camera for

473-554: A year later started the manufacture of 35mm film SLR cameras ; in 1968 it started a glass melting factory. Nikō changed its name to Cosina in 1973. (The first part of the name is a reference to the Koshi area within Nakano, where the founder came from; while the 'Na' represents Nakano.) The name Cosina has previously appeared on compact and SLR cameras for 135 film . The CS-2 and CS-3 SLRs were introduced in 1978, followed in 1980 by

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516-417: Is a lens whose surface profiles are not portions of a sphere or cylinder . In photography , a lens assembly that includes an aspheric element is often called an aspherical lens . The asphere's more complex surface profile can reduce or eliminate spherical aberration and also reduce other optical aberrations such as astigmatism , compared to a simple lens . A single aspheric lens can often replace

559-614: Is a manufacturer of high-end optical glass, optical precision equipment, cameras , video and electronic related equipment, based in Nakano , Nagano Prefecture , Japan . Cosina is the successor to Nikō (or "Nikoh"), a company set up as a lens processing factory in February 1959, which was a pioneer in optical polishing and lens grinding in Japan. In 1966, it also started to manufacture 35 mm compact cameras and 8 mm cine cameras , and

602-400: Is becoming obsolete, replaced by surgical implants of intra-ocular lenses . Many convex types of lens have been approved by governing agencies regulating prescriptions. Concave aspheres are used for the correction of high myopia . They are not commercially available from optical dispensaries, but rather must be specially ordered with instructions from the fitting practitioner, much like how

645-422: Is particularly useful for infrared optics. Several "finishing" methods can be used to improve the precision and surface quality of the polished surface. These include ion-beam finishing, abrasive water jets , and magnetorheological finishing , in which a magnetically guided fluid jet is used to remove material from the surface. Another method for producing aspheric lenses is by depositing optical resin onto

688-638: Is sometimes used. Small glass or plastic aspheric lenses can be made by molding, which allows cheap mass production. Due to their low cost and good performance, molded aspheres are commonly used in inexpensive consumer cameras , camera phones, and CD players. They are also commonly used for laser diode collimation, and for coupling light into and out of optical fibers . Larger aspheres are made by grinding and polishing . Lenses produced by these techniques are used in telescopes , projection TVs , missile guidance systems , and scientific research instruments. They can be made by point-contact contouring to roughly

731-465: Is the sag —the z-component of the displacement of the surface from the vertex , at distance r {\displaystyle r} from the axis. The coefficients α i {\displaystyle \alpha _{i}} describe the deviation of the surface from the axially symmetric quadric surface specified by R {\displaystyle R} and κ {\displaystyle \kappa } . If

774-616: The CT-1 , CT-7 (the world's first all—push-button SLR), CT-10 and CT-20 , the CT-1G in 1982 and the CT-9 in 1986. Cosina SLR cameras used either the M42 (Praktica/Pentax) lens mount or the Pentax K (bayonet) lens mount. However, Cosina is probably better known as a manufacturer of cameras and camera components for other brands, including the popular Yashica FX-3, FX-3 Super, and Super 2000. During

817-896: The Canon T60 , the Nikon FM10 and FE10 , the Olympus OM2000 , Konica TC-X , Yashica FX-3 and FX-3 Super, and various Vivitar models. For this models the CT-1 was used. A Cosina design, the 1982 Cosina CX-2 , was copied by the Russian optical firm LOMO as the popular Lomo LC-A . Cosina manufactures manual focus SLR lenses for Carl Zeiss AG with: Leica (ZM), Nikon (ZF), Pentax (ZK), Canon EOS (ZE), and M42 (ZS) lens screw mounts. Cosina products are distributed in Japan by Kenko . Aspheric lens An aspheric lens or asphere (often labeled ASPH on eye pieces)

860-576: The Epson digital rangefinder camera R-D1 as well. Its manufacture of a new Zeiss Ikon rangefinder camera with Leica M-mount , and Zeiss lenses in Leica bayonet mount, was announced in October 2004, and had begun producing these by April 2006. All these cameras use film. Cosina is also well known for manufacturing 35 mm SLR cameras to the specifications of other manufacturers and distributors, such as

903-583: The R-D1s was released in March 2006. The Epson R-D1s is mechanically identical to the R-D1 , but with a firmware upgrade. It adds: Users of R-D1 could upgrade their camera to have the same functions. The successors of the R-D1s , the R-D1x and R-D1xG were made available from 9 April 2009 in Japan only. They feature very similar feature set except for few modifications: On 17 March 2014, Epson announced that

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946-410: The R-D1x was discontinued. Digital types: M = Professional | ME = Entry level | MM = Monochrom | MD = No display MR = Increased resolution   CCD sensor   |   CMOS sensor   | Video capabilities This camera-related article is a stub . You can help Misplaced Pages by expanding it . Cosina Cosina Co., Ltd. ( 株式会社コシナ , Kabushiki-gaisha Koshina )

989-501: The Schmidt–Cassegrain telescopes . Small molded aspheres are often used for collimating diode lasers . Aspheric lenses are also sometimes used for eyeglasses . Aspheric eyeglass lenses allow for crisper vision than standard "best form" lenses, mostly when looking in other directions than the lens optical center. Moreover, the reduction of the magnification effect of a lens may help with prescriptions that have different powers in

1032-489: The 1620s, and by Christiaan Huygens in the 1670s; the cross-section of the shape devised by Descartes for this purpose is known as a Cartesian oval . The Visby lenses found in Viking treasures on the island of Gotland dating from the 10th or 11th century are also aspheric, but exhibit a wide variety of image qualities, ranging from similar to modern aspherics in one case to worse than spheric lenses in others. The origin of

1075-460: The 2 eyes ( anisometropia ). Not related to the optical quality, they may give a thinner lens, and also distort the viewer's eyes less as seen by other people, producing better aesthetic appearance. While in principle aspheric surfaces can take a wide variety of forms, aspheric lenses are often designed with surfaces of the form where the optic axis is presumed to lie in the z direction, and z ( r ) {\displaystyle z(r)}

1118-558: The Objects more exactly in their respective proportions, and enduring a greater Aperture, free from Colours." Aspheric reading and burning glasses also outdid their spherical equivalents. Moritz von Rohr is usually credited with the design of the first aspheric lenses for eyeglasses. He invented the eyeglass lens designs that became the Zeiss Punktal lenses. The world's first commercial, mass-produced aspheric lens element

1161-548: The President of Cosina since the death in 1988 of his father Kobayashi Bunjirō ( 小林文治郎 ) , the founder. The name Cosina now appears (conspicuously) on lenses for various SLR mounts, and less conspicuously on a widening range of cameras and lenses with the Voigtländer brand. Cosina manufactured the rangefinder camera Rollei 35 RF for Rollei Fototechnic , and is acknowledged to have manufactured (and to have helped design)

1204-650: The Voigtländer 15 mm f/4.5 and 25 mm f/4 lens (neither of them rangefinder-coupled) and the Voigtländer Bessa-L standard camera body. It quickly followed with a wider range of Voigtländer cameras (starting with the Bessa-R , with viewfinder and rangefinder, and the Bessa-T , with rangefinder, but no viewfinder), and a set of lenses, including the Heliar 12 mm f/5.6 lens, which on its introduction

1247-711: The amateur film photography sector — similar to a rangefinder camera, but without a rangefinder or viewfinder — for mounting these lenses. In 1999, Cosina secured partial rights to the German, once Austrian, classic camera brand " Voigtländer ", acquired from RINGFOTO GmbH & Co. ALFO Marketing KG in Germany , to produce the Classic Collection (high-quality lenses with both M39 screw thread and Leica M bayonet, 35mm film cameras Bessa R, Bessa L, Bessa T, and medium format cameras Bessa III). Cosina first introduced

1290-558: The anterior surface of the lens. The blended curvature of aspheres reduces scotoma , a ringed blind spot. Aspheric elements are often used in camera lenses. This is often indicated by the abbreviation ASPH in the names of such products. Ibn sahl , a 10th century Arab physicist figured out that a combination of spherical and parabolic surfaces, which is now known as anaclastic lens or aspheric lens, focuses light with minimal aberration. Early attempts at making aspheric lenses to correct spherical aberration were made by René Descartes in

1333-399: The coefficients α i {\displaystyle \alpha _{i}} are all zero, then R {\displaystyle R} is the radius of curvature and κ {\displaystyle \kappa } is the conic constant , as measured at the vertex (where r = 0 {\displaystyle r=0} ). In this case, the surface has

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1376-439: The curvature of a lens, but the polish quality of the resulting surfaces is not as good as those achieved with lapidary techniques. Standards for the dispensing of prescription eyeglass lenses discourage the use of curvatures that deviate from definite focal lengths. Multiple focal lengths are accepted in the form of bifocals , trifocals , vari-focals, and cylindrical components for astigmatism . Measurement technology plays

1419-474: The design of the lens curvature already progresses toward a less-minus/more-plus dioptric power from the center of the lens to the edge. High plus aspheres for hyperopes progress toward less-plus at the periphery. The aspheric curvature on high plus lenses are ground on the anterior side of the lens, whereas the aspheric curvature of high minus lenses are ground onto the posterior side of the lens. Progressive add reading portions for plus lenses are also ground onto

1462-491: The determination of deviations of the lens from the target shape in an interference image. CGHs must be manufactured specifically for each test item and are therefore only economical for series production. Another possibility is the interferometric measurement of aspheres in subareas, with minimal deviations to the best-fit sphere, and subsequent combination of the submeasurements to a full-surface interferogram. These are very flexible in comparison to CGHs and are also suitable for

1505-486: The form of a conic section rotated about the optic axis, with form determined by κ {\displaystyle \kappa } : The above equation suffers from strong correlation between the coefficients of the first term and the polynomial terms. This leads to strong divergences when it comes to fitting the equation to an aspheric surface. Therefore, different equations using "Q-polynomials" where coefficients are orthogonal to each other are an alternative that

1548-482: The late 1970s, Cosina made a name for itself in 35 mm rangefinder cameras with a well-built, high quality fixed-lens camera using an aluminum body and a simple shutter-priority autoexposure system. This rangefinder camera was adopted as the basic chassis for several excellent camera models, including the Minolta 7SII , Revue 400 SE , Prinz 35 ER , and Vivitar 35 ES . In 1982, Cosina began to manufacture lenses in

1591-485: The lenses is unknown, as is their purpose (they may have been made as jewelry rather than for imaging). Francis Smethwick ground the first high-quality aspheric lenses and presented them to the Royal Society on February 27, 1667/8 . A telescope containing three aspheric elements was judged by those present "to exceed [a common, but very good telescope] in goodness, by taking in a greater Angle and representing

1634-495: The production of prototypes and small series. Like other lenses for vision correction , aspheric lenses can be categorized as convex or concave. Convex aspheric curvatures are used in many presbyopic vari-focal lenses to increase the optical power over part of the lens, aiding in near-pointed tasks such as reading. The reading portion is an aspheric "progressive add". Also, in aphakia or extreme hyperopia , high plus power aspheric lenses can be prescribed, but this practice

1677-461: The right form which is then polished to its final shape. In other designs, such as the Schmidt systems, the aspheric corrector plate can be made by using a vacuum to distort an optically parallel plate into a curve which is then polished "flat" on one side. Aspheric surfaces can also be made by polishing with a small tool with a compliant surface that conforms to the optic, although precise control of

1720-484: The shape of the asphere and to adjust the following operation. A profile gauge probe is used to measure a section across the lens surface. The rotation symmetry of the lenses means that the combination of several of these profiles provides a sufficiently precise knowledge of the shape of the lens. Any damage to the lens surface caused by the probe tip would be removed in subsequent steps. Interferometers are used when measuring sensitive or polished surfaces. By superimposing

1763-443: The surface form and quality is difficult, and the results may change as the tool wears. Single-point diamond turning is an alternate process, in which a computer-controlled lathe uses a diamond tip to directly cut the desired profile into a piece of glass or another optical material. Diamond turning is slow and has limitations in the materials on which it can be used, and the surface accuracy and smoothness that can be achieved. It

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1806-488: Was manufactured by Elgeet for use in the Golden Navitar 12 mm f /1.2 normal lens for use on 16 mm movie cameras in 1956. This lens received a great deal of industry acclaim during its day. The aspheric elements were created by the use of a membrane polishing technique. The optical quality of a lens system can be tested in an optics or physics laboratory using bench apertures, optic tubes, lenses, and

1849-600: Was the widest rectilinear lens ever marketed for still photography. On April 26, 2010, Cosina joined the Micro Four Thirds System Standard Group. In 2016, Cosina manufactured a Nokton 1,4/ 58 mm after 2003 a second time. For this lenses a Topcon -construction was used. Cosina's "Voigtländer" products are sometimes referred to as Cosina Voigtländer . The Cosina Voigtländer cameras and lenses have been of great personal interest to Kobayashi Hirofumi ( 小林博文 ) ( b. 1953),

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