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Waterhouse Stop
The Waterhouse stop or Waterhouse diaphragm is an interchangeable diaphragm with an aperture (hole) for controlling the entry of light into a camera. A thin piece of metal (the diaphragm) is drilled with a hole (the aperture); a set of these with varying hole sizes makes up a set of Waterhouse stops, corresponding to what today we call f-stops or f-numbers. Photographic lens makers provided slots in lens barrels for the insertion of the chosen stop. This apparatus was invented by the pioneering 19th-century photographer John Waterhouse of Halifax in 1858. It has also been reported to have been independently invented by Mr. H. R. Smyth, and described by Waterhouse as early as 1856. The innovation was quickly put to use due to its convenience: "Aperture openings were at first controlled by unscrewing the lens and inserting stops of the appropriate size between the lens components, though after 1858 photographers used the more convenient Waterhouse stops which eliminated unscrew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dallmeyer Waterhouse
Dallmeyer may refer to: People People with the surname Dallmeyer include: * William Q. Dallmeyer (1829–1908), German-born Missouri politician * John Henry Dallmeyer (1830–1883), Anglo-German optician ** His son Thomas Rudolphus Dallmeyer (1859–1906), English optician ** J H Dallmeyer Ltd, the lens manufacturing business that they founded * Andrew Dallmeyer Andrew Dallmeyer (10 January 1945 – 21 May 2017) was a Scottish playwright, theatre director and actor. He wrote over 75 plays, including the ''Opium Eater'' and directed more than 50 productions. His plays have won a number of awards, includi ... (1945–2017), Scottish playwright, theatre director and actor Places * Dallmeyer Peak, a peak in Argentinian Antarctica {{Disambiguation, surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diaphragm (optics)
In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to ''stop'' the passage of light, except for the light passing through the ''aperture''. Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses). The diaphragm is placed in the light path of a lens or objective, and the size of the aperture regulates the amount of light that passes through the lens. The centre of the diaphragm's aperture coincides with the optical axis of the lens system. Most modern cameras use a type of adjustable diaphragm known as an iris diaphragm, and often referred to simply as an iris. See the articles on aperture and f-number for the photographic effect and system of quantification of varying the opening in the diaphragm. Iris diaphragms versus other types A natural optical system that has a diaphragm an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An optical system typically has many openings or structures that limit the ray bundles (ray bundles are also known as ''pencils'' of light). These structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that primarily determines the ray cone angle and brightness at the image point. In some contexts, especially in photography and astronomy, ''aperture'' refers to the diameter of the aperture stop rather than the physical stop or the opening itself. For example, in a telescope, the aperture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camera
A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a small hole (the aperture) that allows light to pass through in order to capture an image on a light-sensitive surface (usually a Image sensor, digital sensor or photographic film). Cameras have various mechanisms to control how the light falls onto the light-sensitive surface. Lenses focus the light entering the camera, and the aperture can be narrowed or widened. A Shutter (photography), shutter mechanism determines the amount of time the photosensitive surface is exposed to the light. The still image camera is the main instrument in the art of photography. Captured images may be reproduced later as part of the process of photography, digital imaging, or photographic printing. Similar artistic fields in the moving-image camera dom ... [...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 diameter ... [...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] |
John Waterhouse (astronomer)
John Waterhouse (3 August 1806 – 13 February 1879) was a British astronomer and meteorologist who invented Waterhouse stops. ] He was born at Well Head House in Halifax, Yorkshire the eldest son of John and Grace Elizabeth (née Rawson) Waterhouse. Well Head had extensive gardens with greenhouses and a staff of 6 gardeners. They cultivated exotic ferns, including a Leptopteris, todea superba which Waterhouse had imported from New Zealand in 1860 and which is now at Kew Gardens. At the house, he built an observatory and meteorological station. Louis John Crossley studied at his laboratory. In 1834 he was President of the Halifax Mechanics' Institute. In the same year he was elected as a Fellow of the Royal Society. He was also a Fellow of the Royal Astronomical Society. In 1839 he travelled around the world for health reasons. Over a period of 8 years (1866–1873), he made detailed observations of the weather and of the night skies from Well Head, which he published in 187 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Enlarger
An enlarger is a specialized transparency projector used to produce photographic prints from film or glass negatives, or from transparencies. Construction All enlargers consist of a light source, normally an incandescent light bulb shining though a condenser or translucent screen to provide even illumination, a holder for the negative or transparency, and a specialized lens for projection. The light passes through a film holder, which holds the exposed and developed photographic negative or transparency. Prints made with an enlarger are called ''enlargements''. Typically, enlargers are used in a darkroom, an enclosed space from which extraneous light may be excluded; some commercial enlargers have an integral dark box so that they can be used in a light-filled room. History Josef Maria Eder, in his ''History of Photography'' attributes the invention of photographic enlargement to Humphry Davy who realised the idea of using a solar microscope to project images onto sensit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darkroom
A darkroom is used to process photographic film, to make prints and to carry out other associated tasks. It is a room that can be made completely dark to allow the processing of the light-sensitive photographic materials, including film and photographic paper. Various equipment is used in the darkroom, including an enlarger, baths containing chemicals, and running water. Darkrooms have been used since the inception of photography in the early 19th century. Darkrooms have many various manifestations, from the elaborate space used by Ansel Adams to a retooled ambulance wagon used by Timothy H. O'Sullivan. From the initial development of the film to the creation of prints, the darkroom process allows complete control over the medium. Due to the popularity of color photography and complexity of processing color film (''see C-41 process'') and printing color photographs and also to the rise, first of instant photography technology and later digital photography, darkrooms are dec ... [...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] |
Lensbaby
Lensbaby is a line of camera lenses for DSLR and mirrorless cameras that combine a simple lens with a bellows or ball and socket mechanism for use in special-effect photography. A lensbaby can give effects normally associated with view cameras. The lenses are for use in selective focus photography and bokeh effects. Overview Lensbaby lenses can be used with most cameras that accept interchangeable lenses, mainly DSLR, SLR, mirrorless, 35mm film and PL mount motion cameras. The focus front standard can be manipulated off axis to move the sharpest area of Focus (called the "sweet spot") to almost anywhere in the frame. This allows the important part of the subject to be rendered fairly sharp with everything else out of focus, even if it is the same distance from the camera. The Lensbaby naturally focuses at approximately 2 feet; closer focus is achieved by pushing the front of the lens out, and infinity focus is achieved by pulling the front of the lens toward the base of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
