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Bokeh
In photography, bokeh ( or ; ) is the aesthetic quality of the blur produced in out-of-focus parts of an image. Bokeh has also been defined as "the way the lens renders out-of-focus points of light". Differences in lens aberrations and aperture shape cause very different bokeh effects. Some lens designs blur the image in a way that is pleasing to the eye, while others produce distracting or unpleasant blurring ("good" and "bad" bokeh, respectively). Photographers may deliberately use a shallow focus technique to create images with prominent out-of-focus regions, accentuating their lens's bokeh. Bokeh is often most visible around small background highlights, such as specular reflections and light sources, which is why it is often associated with such areas. However, bokeh is not limited to highlights; blur occurs in all regions of an image which are outside the depth of field. The opposite of bokeh—an image in which multiple distances are visible and all are in fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bokeh
In photography, bokeh ( or ; ) is the aesthetic quality of the blur produced in out-of-focus parts of an image. Bokeh has also been defined as "the way the lens renders out-of-focus points of light". Differences in lens aberrations and aperture shape cause very different bokeh effects. Some lens designs blur the image in a way that is pleasing to the eye, while others produce distracting or unpleasant blurring ("good" and "bad" bokeh, respectively). Photographers may deliberately use a shallow focus technique to create images with prominent out-of-focus regions, accentuating their lens's bokeh. Bokeh is often most visible around small background highlights, such as specular reflections and light sources, which is why it is often associated with such areas. However, bokeh is not limited to highlights; blur occurs in all regions of an image which are outside the depth of field. The opposite of bokeh—an image in which multiple distances are visible and all are in fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shallow Focus
Shallow focus is a photographic and cinematographic technique incorporating a small depth of field. In shallow focus, one plane of the scene is in focus while the rest is out of focus. Shallow focus is typically used to emphasize one part of the image over another. Photographers sometimes refer to the aesthetic quality of the unfocused area(s) as bokeh. The opposite of shallow focus is deep focus, in which the entire image is in focus. Overview Shallow focus has become more popular in the 2000s and 2010s. It is also a means by which low budget filmmakers use to hide places that would require expensive props. It is often proclaimed by some to being a way to avoid the "video look." Extremely shallow focus – sometimes called ''bokeh porn'' – made its debut in cinematography in 2008 with the release of the Canon EOS 5D Mark II and the start of DSLR cinematography. Details The effect can be obtained by a larger aperture, a close viewpoint, a larger image sensor or a longer f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Focus
Deep focus is a photographic and cinematographic technique using a large depth of field. Depth of field is the front-to-back range of focus in an image, or how much of it appears sharp and clear. In deep focus, the foreground, middle ground, and background are all in focus. Deep focus is normally achieved by choosing a small aperture. Since the aperture of a camera determines how much light enters through the lens, achieving deep focus requires a bright scene or long exposure. A wide-angle lens also makes a larger portion of the image appear sharp. It is also possible to achieve the illusion of deep focus with optical tricks (split-focus diopter) or by compositing two or more images together. The opposite of deep focus is shallow focus, in which the plane of the image that is in focus is very shallow. For example, the foreground might be in focus while the middle-ground and background are out-of-focus. When avoiding deep focus is used specifically for aesthetic effect—espe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catadioptric System
A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses ( dioptrics) and curved mirrors ( catoptrics). Catadioptric combinations are used in focusing systems such as searchlights, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses. Other optical systems that use lenses and mirrors are also referred to as "catadioptric", such as surveillance catadioptric sensors. Early catadioptric systems Catadioptric combinations have been used for many early optical systems. In the 1820s, Augustin-Jean Fresnel developed several catadioptric lighthouse reflectors. Léon Foucault developed a catadioptric microscope in 1859 to counteract aberrations of using a lens to image objects at high power. In 1876 a French engineer, A. Mangin, invented what has come to be called the Mangin mirror, a concave glass reflector with the silver surface on the rear side of the glass. The t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meyer Optik Görlitz
Meyer Optik Görlitz (or Goerlitz; German), originally Hugo Meyer & Co., was a former optical company from Görlitz in Germany. It was founded in 1896 by optician Hugo Meyer (May 21, 1863 - March 1, 1905) and businessman Heinrich Schätze. The company got off to a successful start with the development of the wide-angle Aristostigmat lens and the subsequent acquisition of Optical Institute Schulze and Billerbeck, the manufacturers of “Euryplan lenses”, as they were called at the time. History A key business decision was made in 1920 when the company decided to work with former Zeiss developer Paul Rudolph, who was previously significantly involved in the success of the Protar, Planar and Tessar lenses. Rudolph also gave Meyer Optik access to his patent for the so-called Plasmat lenses, which at the time included one of the most powerful lenses in the world. In 1936, the company was renamed Optische und Feinmechanische Werke Hugo Meyer & Co and produced approximately 100,0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F-number
In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill Professional, p. 183. It is also known as the focal ratio, f-ratio, or f-stop, and is very important in photography. It is a dimensionless number that is a quantitative measure of lens speed; increasing the f-number is referred to as ''stopping down''. The f-number is commonly indicated using a lower-case hooked f with the format ''N'', where ''N'' is the f-number. The f-number is the reciprocal of the relative aperture (the aperture diameter divided by focal length). Notation The f-number is given by: N = \frac \ where f is the focal length, and D is the diameter of the entrance pupil (''effective aperture''). It is customary to write f-numbers preceded by "", which forms a mathematical expression of the entrance pupil diamet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circle Of Confusion
In optics, a circle of confusion (CoC) is an optical spot caused by a cone of light rays from a lens not coming to a perfect focus when imaging a point source. It is also known as disk of confusion, circle of indistinctness, blur circle, or blur spot. In photography, the circle of confusion is used to determine the depth of field, the part of an image that is acceptably sharp. A standard value of CoC is often associated with each image format, but the most appropriate value depends on visual acuity, viewing conditions, and the amount of enlargement. Usages in context include ''maximum permissible circle of confusion'', ''circle of confusion diameter limit'', and the ''circle of confusion criterion''. Real lenses do not focus all rays perfectly, so that even at best focus, a point is imaged as a spot rather than a point. The smallest such spot that a lens can produce is often referred to as the circle of least confusion. Two uses Two important uses of this term and conce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spherical Aberration
In optics, spherical aberration (SA) is a type of aberration found in optical systems that have elements with spherical surfaces. Lenses and curved mirrors are prime examples, because this shape is easier to manufacture. Light rays that strike a spherical surface off-centre are refracted or reflected more or less than those that strike close to the centre. This deviation reduces the quality of images produced by optical systems. Overview A spherical lens has an aplanatic point (i.e., no spherical aberration) only at a radius that equals the radius of the sphere divided by the index of refraction of the lens material. A typical value of refractive index for crown glass is 1.5 (see list), which indicates that only about 43% of the area (67% of diameter) of a spherical lens is useful. It is often considered to be an imperfection of telescopes and other instruments which makes their focusing less than ideal due to the spherical shape of lenses and mirrors. This is an important ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Josefina With Bokeh
Josefina is a female name, a feminine form of Joseph. It may refer to: * Josefina Passadori, Argentine writer *Josefina Lopez, Chicana playwright * Josefina Pla, Spanish poet, playwright, art critic, painter and journalist * Josefina Ayerza, writer and a psychoanalyst *Josefina Deland, Swedish feminist *Josefina Muñoz, Chilean artist *Josefina Wettergrund, Swedish writer Fiction *Josefina LaCosta, a fictional character in the Richard Sharpe series of novels by Bernard Cornwell. *Josefina, Gil Harris' fake girlfriend in the 2002 teen comedy '' The New Guy'' *Josefina Menendez, a fictional character in the 2012 first-person shooter '' Call of Duty: Black Ops II''. *Josefina Montoya Josefina is a female name, a feminine form of Joseph. It may refer to: *Josefina Passadori, Argentine writer *Josefina Lopez, Chicana playwright * Josefina Pla, Spanish poet, playwright, art critic, painter and journalist * Josefina Ayerza, write ..., the fictional main character of the American Girl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygon
In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed '' polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two together, may be called a polygon. The segments of a polygonal circuit are called its ''edges'' or ''sides''. The points where two edges meet are the polygon's '' vertices'' (singular: vertex) or ''corners''. The interior of a solid polygon is sometimes called its ''body''. An ''n''-gon is a polygon with ''n'' sides; for example, a triangle is a 3-gon. A simple polygon is one which does not intersect itself. Mathematicians are often concerned only with the bounding polygonal chains of simple polygons and they often define a polygon accordingly. A polygonal boundary may be allowed to cross over itself, creating star polygons and other self-intersecting polygons. A polygon is a 2-dimensional example of the more general polytope in any nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macro Lens
Macro photography (or photomacrography or macrography, and sometimes macrophotography) is extreme close-up photography, usually of very small subjects and living organisms like insects, in which the size of the subject in the photograph is greater than life size (though ''macrophotography'' also refers to the art of making very large photographs). By the original definition, a macro photograph is one in which the size of the subject on the negative or image sensor is life size or greater. In some senses, however, it refers to a finished photograph of a subject that is greater than life size. The ratio of the subject size on the film plane (or sensor plane) to the actual subject size is known as the reproduction ratio. Likewise, a macro lens is classically a lens capable of reproduction ratios of at least 1:1, although it often refers to any lens with a large reproduction ratio, despite rarely exceeding 1:1. Apart from technical photography and film-based processes, where the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Mirror
A secondary mirror (or secondary) is the second deflecting or focusing mirror element in a reflecting telescope. Light gathered by the primary mirror is directed towards a focal point typically past the location of the secondary. Secondary mirrors in the form of an optically flat ''diagonal mirror'' are used to re-direct the light path in designs such as Newtonian reflectors. They are also used to re-direct and extend the light path and modify the final image in designs such as Cassegrain reflectors. The secondary is typically suspended by X-shaped struts (sometimes called a "spider") in the path of light between the source and the primary, but can be mounted on other types of mounts or optical elements such as optical windows, or schmidt and meniscus corrector plates. Employing secondary mirrors in optical systems causes some image distortion due to the obstruction of the secondary itself, and distortion from the spider mounts, commonly seen as cross-shaped diffraction spikes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
