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Photographic Lens Design
The design of photographic lenses for use in still or cine cameras is intended to produce a lens that yields the most acceptable rendition of the subject being photographed within a range of constraints that include cost, weight and materials. For many other optical devices such as telescopes, microscopes and theodolites where the visual image is observed but often not recorded the design can often be significantly simpler than is the case in a camera where every image is captured on film or image sensor and can be subject to detailed scrutiny at a later stage. Photographic lenses also include those used in enlargers and projectors. Design Design requirements From the perspective of the photographer, the ability of a lens to capture sufficient light so that the camera can operate over a wide range of lighting conditions is important. Designing a lens that reproduces colour accurately is also important as is the production of an evenly lit and sharp image over the whole of the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Lens
A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically. There is no major difference in principle between a lens used for a still camera, a video camera, a telescope, a microscope, or other apparatus, but the details of design and construction are different. A lens might be permanently fixed to a camera, or it might be interchangeable with lenses of different focal lengths, apertures, and other properties. While in principle a simple convex lens will suffice, in practice a compound lens made up of a number of optical lens elements is required to correct (as much as possible) the many optical aberrations that arise. Some aberrations will be present in any lens system. It is the job of the lens designer to balance these and produce a desi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed Focus
A photographic lens for which the focus is not adjustable is called a fixed-focus lens or sometimes focus-free. The focus is set at the time of lens design, and remains fixed. It is usually set to the hyperfocal distance, so that the depth of field ranges all the way down from half that distance to infinity, which is acceptable for most cameras used for capturing images of humans or objects larger than a meter. Rather than having a method of determining the correct focusing distance and setting the lens to that focal point, a fixed-focus lens relies on sufficient depth of field to produce acceptably sharp images. Most cameras with focus-free lenses also have a relatively small aperture, which increases the depth of field. Fixed-focus cameras with extended depth of field (EDOF) sometimes are known as full-focus cameras. Concept In order to reach a minimal focal distance, the aperture and the focal length of the lens are reduced (a slow wide-angle lens), to make the hyperfocal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abbe Number
In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of ''V'' indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German physicist who defined it. The term V-number should not be confused with the normalized frequency in fibers. The Abbe number, ''Vd'', of a material is defined as :V_D = \frac, where ''n''C, ''n''d and ''n''F are the refractive indices of the material at the wavelengths of the Fraunhofer ''C'', ''d'', and ''F'' spectral lines (656.3 nm, 587.56 nm, and 486.1 nm respectively). This formulation only applies to the visible spectrum. Outside this range requires the use of different spectral lines. For non-visible spectral lines the term V-number is more commonly used. The more general formulation defined as, :V = \frac, where ''n''short, ''n''cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeiss Otus 55mm F1
Zeiss or Zeiß may refer to: People *Carl Zeiss (1816–1888), German optician and entrepreneur *Emil Zeiß (1833–1910), German Protestant minister and painter Companies *Carl Zeiss AG, German manufacturer of optics, industrial measurements and medical devices founded by Carl Zeiss *Carl Zeiss Foundation, holding company for several Zeiss companies *Carl Zeiss Meditec AG, a Zeiss subsidiary *Carl Zeiss SMT, a Zeiss subsidiary *Schott AG, a Zeiss subsidiary Institutions and organizations *Carl-Zeiss-Gymnasium Jena a School in Jena, Germany. *FC Carl Zeiss Jena, football club founded in 1903 by workers at Carl Zeiss optics company Technologies *Zeiss formula, a formula for depth of field calculations. *Zeiss projector, a line of planetarium projectors manufactured by one of the Zeiss companies *Zeiss Planar, a photographic lens patented by the Zeiss company in 1896 *Zeiss Sonnar, a photographic lens patented by the Zeiss company in 1924 *Zeiss Tessar, a photographic lens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatic Aberration
In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength. Since the focal length of a lens depends on the refractive index, this variation in refractive index affects focusing. Chromatic aberration manifests itself as "fringes" of color along boundaries that separate dark and bright parts of the image. Types There are two types of chromatic aberration: ''axial'' (''longitudinal''), and ''transverse'' (''lateral''). Axial aberration occurs when different wavelengths of light are focused at different distances from the lens (focus ''shift''). Longitudinal aberration is typical at long focal lengths. Transverse aberration occurs when different wavelengths are focused at different positions i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractive Index
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or refracted, when entering a material. This is described by Snell's law of refraction, , where ''θ''1 and ''θ''2 are the angle of incidence and angle of refraction, respectively, of a ray crossing the interface between two media with refractive indices ''n''1 and ''n''2. The refractive indices also determine the amount of light that is reflected when reaching the interface, as well as the critical angle for total internal reflection, their intensity ( Fresnel's equations) and Brewster's angle. The refractive index can be seen as the factor by which the speed and the wavelength of the radiation are reduced with respect to their vacuum values: the speed of light in a medium is , and similarly the wavelength in that medium is , where ''Π... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens Mount
A lens mount is an interface – mechanical and often also electrical – between a photographic camera body and a lens. It is a feature of camera systems where the body allows interchangeable lenses, most usually the rangefinder camera, single lens reflex type, single lens mirrorless type or any movie camera of 16 mm or higher gauge. Lens mounts are also used to connect optical components in instrumentation that may not involve a camera, such as the modular components used in optical laboratory prototyping which join via C-mount or T-mount elements. Mount types A lens mount may be a screw-threaded type, a bayonet-type, or a breech-lock (friction lock) type. Modern still camera lens mounts are of the bayonet type, because the bayonet mechanism precisely aligns mechanical and electrical features between lens and body. Screw-threaded mounts are fragile and do not align the lens in a reliable rotational position, yet types such as the C-mount interface are still widely in us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayonet Mount
A bayonet mount (mainly as a method of mechanical attachment, such as fitting a lens to a camera using a matching lens mount) or bayonet connector (for electrical use) is a fastening mechanism consisting of a cylindrical male side with one or more radial pins, and a female receptor with matching L-shaped slot(s) and with spring(s) to keep the two parts locked together. The slots are shaped like a capital letter L with serif (a short upward segment at the end of the horizontal arm); the pin slides into the vertical arm of the L, rotates across the horizontal arm, then is pushed slightly upwards into the short vertical "serif" by the spring; the connector is no longer free to rotate unless pushed down against the spring until the pin is out of the "serif". The bayonet mount is the standard light bulb fitting in the United Kingdom and in many countries that were members of the British Empire including Pakistan, Australia, Hong Kong, Fiji India, Sri Lanka, Ireland, and New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elmar (lens)
The name Elmar is used by Leica to designate camera lenses of four elements that have a maximum aperture of f/3.98 or f/4.0. History The Elmar lenses originally had a maximum aperture of f/3.5. These lenses were derived from a 50 mm f/3.5 Elmax lens first produced in 1925. The name is a combination of Ernst Leitz and Max Berek. Description Elmar lenses variously has a maximum f-number of f/2.8 or f/3.4 or f/3.8 or f/4. Currently the Elmar lenses have a maximum aperture of f/3.8 or f/4, as in the Elmar-M 24 mm f/3.8 and Tri-Elmar-M 16-18-21 mm f/4. The name Elmar is sometimes combined with: Super, Tele, APO, Macro or Vario. Market positions Elmar lenses are comparatively slow. As a result they tend to be smaller and lighter than faster lenses of the same focal length. List of Elmar lenses ;For the M39 lens mount: * Elmar 50 mm collapsible * Elmar 90mm ;For the Leica M mount The Leica M mount is a camera lens mount introduced in 1954 with the Leica M3, and a range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leica Camera
Leica Camera AG () is a German company that manufactures cameras, optical lenses, photographic lenses, binoculars, Telescopic sight, rifle scopes and microscopes. The company was founded by Ernst Leitz in 1869 (Ernst Leitz Wetzlar), in Wetzlar, Germany. In 1986, the Leitz company changed its name to Leica, due to the fame of the Leica trade-name. The name Leica is derived from the first three letters of the founder's surname (Leitz) and the first two of the word camera: lei-ca (LEItz CAmera). At this time, Leica relocated its factory from Wetzlar to the nearby town of Solms. Leica Camera AG is 55% owned by Austrian investment firm ACM Projektentwicklung GmbH, and 45% owned by The Blackstone Group which licenses the Leica brand name from the Danaher Corporation-owned Leica Microsystems GmbH. History From the year 1907 to the 1950s, the buildings that formed Leica factory were built on Ernst Leitz Street in Wetzlar, and remained until 1986, when the factory was moved to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tessar
The Tessar is a photographic lens design conceived by the German physicist Paul Rudolph in 1902 while he worked at the Zeiss optical company and patented by Zeiss in Germany; the lens type is usually known as the Zeiss Tessar. A Tessar comprises four elements in three groups, one positive crown glass element at the front, one negative flint glass element at the center and a negative plano-concave flint glass element cemented with a positive convex crown glass element at the rear. History Beginnings Despite common belief, the Tessar was not developed from the 1893 Cooke triplet design by replacing the rear element with a cemented achromatic doublet. Paul Rudolph designed the Anastigmat with two lenses cemented in 1890. Later, Rudolph thought that a narrow airgap in the form of a positive lens would correct the spherical aberration (as did HL Aldis in 1895) and that this device was much better than the lenses cemented. In addition, this allowed the photographers to hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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