1.
Photography
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Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. With an electronic sensor, this produces an electrical charge at each pixel. A negative image on film is used to photographically create a positive image on a paper base, known as a print. The word photography was created from the Greek roots φωτός, genitive of φῶς, light and γραφή representation by means of lines or drawing, several people may have coined the same new term from these roots independently. Johann von Maedler, a Berlin astronomer, is credited in a 1932 German history of photography as having used it in an article published on 25 February 1839 in the German newspaper Vossische Zeitung. Both of these claims are now widely reported but apparently neither has ever been confirmed as beyond reasonable doubt. Credit has traditionally given to Sir John Herschel both for coining the word and for introducing it to the public. Photography is the result of combining several technical discoveries, later Greek mathematicians Aristotle and Euclid also independently described a pinhole camera in the 5th and 4th centuries BCE. Daniele Barbaro described a diaphragm in 1566, wilhelm Homberg described how light darkened some chemicals in 1694. The fiction book Giphantie, published in 1760, by French author Tiphaigne de la Roche, the discovery of the camera obscura that provides an image of a scene dates back to ancient China. Leonardo da Vinci mentions natural camera obscura that are formed by dark caves on the edge of a sunlit valley, a hole in the cave wall will act as a pinhole camera and project a laterally reversed, upside down image on a piece of paper. So the birth of photography was primarily concerned with inventing means to capture, renaissance painters used the camera obscura which, in fact, gives the optical rendering in color that dominates Western Art. The camera obscura literally means dark chamber in Latin and it is a box with a hole in it which allows light to go through and create an image onto the piece of paper. Around the year 1800, British inventor Thomas Wedgwood made the first known attempt to capture the image in a camera obscura by means of a light-sensitive substance and he used paper or white leather treated with silver nitrate. The shadow images eventually darkened all over, the first permanent photoetching was an image produced in 1822 by the French inventor Nicéphore Niépce, but it was destroyed in a later attempt to make prints from it. Niépce was successful again in 1825, in 1826 or 1827, he made the View from the Window at Le Gras, the earliest surviving photograph from nature. Because Niépces camera photographs required a long exposure, he sought to greatly improve his bitumen process or replace it with one that was more practical. With an eye to eventual commercial exploitation, the partners opted for total secrecy, Daguerres efforts culminated in what would later be named the daguerreotype process
2.
Camera
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Thumb|A2016 Nikon D810 A camera is an optical instrument for recording or capturing images, which may be stored locally, transmitted to another location, or both. The images may be individual still photographs or sequences of images constituting videos or movies, the camera is a remote sensing device as it senses subjects without physical contact. The word camera comes from camera obscura, which means dark chamber and is the Latin name of the device for projecting an image of external reality onto a flat surface. The modern photographic camera evolved from the camera obscura, the functioning of the camera is very similar to the functioning of the human eye. A camera may work with the light of the spectrum or with other portions of the electromagnetic spectrum. A still camera is a device which creates a single image of an object or scene. All cameras use the basic design, light enters an enclosed box through a converging lens/convex lens. A shutter mechanism controls the length of time that light can enter the camera, a display, often a liquid crystal display, permits the user to view scene to be recorded and settings such as ISO speed, exposure, and shutter speed. A movie camera or a video camera operates similarly to a camera, except it records a series of static images in rapid succession. When the images are combined and displayed in order, the illusion of motion is achieved, the forerunner to the photographic camera was the camera obscura. The oldest known record of this principle is a description by Han Chinese philosopher Mozi, Mozi correctly asserted that the camera obscura image is inverted because light travels in straight lines from its source. In the 11th century Arab physicist Ibn al-Haytham s wrote very influential essays about experiments with light through an opening in a darkened room. The use of a lens in the opening of a wall or closed window shutter of a room to project images used as a drawing aid has been traced back to circa 1550. Since the late 17th century portable camera obscura devices in tents, before the development of the photographic camera, it had been known for hundreds of years that some substances, such as silver salts, darkened when exposed to sunlight. The first person to use this chemistry to create images was Thomas Wedgwood, to create images, Wedgwood placed items, such as leaves and insect wings, on ceramic pots coated with silver nitrate, and exposed the set-up to light. These images werent permanent, however, as Wedgwood didnt employ a fixing mechanism and he ultimately failed at his goal of using the process to create fixed images created by a camera obscura. The first permanent photograph of an image was made in 1826 by Joseph Nicéphore Niépce using a sliding wooden box camera made by Charles. Niépce had been experimenting with ways to fix the images of a camera obscura since 1816, the photograph Niépce succeeded in creating shows the view from his window
3.
Flash (photography)
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A flash is a device used in photography producing a flash of artificial light at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a dark scene, other uses are capturing quickly moving objects or changing the quality of light. Flash refers either to the flash of light itself or to the flash unit discharging the light. Most current flash units are electronic, having evolved from single-use flashbulbs, modern cameras often activate flash units automatically. Flash units are built directly into a camera. Some cameras allow separate flash units to be mounted via an accessory mount bracket. In professional studio equipment, flashes may be large, standalone units, or studio strobes, studies of magnesium by Bunsen and Roscoe in 1859 showed that burning this metal produced a light with similar qualities to daylight. The potential application to photography inspired Edward Sonstadt to investigate methods of manufacturing magnesium so that it would burn reliably for this use and he applied for patents in 1862 and by 1864 had started the Manchester Magnesium Company with Edward Mellor. It also had the benefit of being a simpler and cheaper process than making round wire, mather was also credited with the invention of a holder for the ribbon, which formed a lamp to burn it in. The packaging also implies that the ribbon was not necessarily broken off before being ignited. An alternative to ribbon was flash powder, a mixture of powder and potassium chlorate, introduced by its German inventors Adolf Miethe. A measured amount was put into a pan or trough and ignited by hand, producing a brilliant flash of light, along with the smoke. This could be an activity, especially if the flash powder was damp. An electrically triggered flash lamp was invented by Joshua Lionel Cowen in 1899 and his patent describes a device for igniting photographers’ flash powder by using dry cell batteries to heat a wire fuse. Variations and alternatives were touted from time to time and a few found a measure of success in the marketplace, especially for amateur use. The use of powder in an open lamp was replaced by flashbulbs, magnesium filaments were contained in bulbs filled with oxygen gas. Manufactured flashbulbs were first produced commercially in Germany in 1929, such a bulb could only be used once, and was too hot to handle immediately after use, but the confinement of what would otherwise have amounted to a small explosion was an important advance. A later innovation was the coating of flashbulbs with a film to maintain bulb integrity in the event of the glass shattering during the flash
4.
Aluminium
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Aluminium or aluminum is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal, Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is combined in over 270 different minerals. The chief ore of aluminium is bauxite, Aluminium is remarkable for the metals low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the industry and important in transportation and structures, such as building facades. The oxides and sulfates are the most useful compounds of aluminium, despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals. Because of these salts abundance, the potential for a role for them is of continuing interest. Aluminium is a soft, durable, lightweight, ductile. It is nonmagnetic and does not easily ignite, a fresh film of aluminium serves as a good reflector of visible light and an excellent reflector of medium and far infrared radiation. The yield strength of aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has about one-third the density and stiffness of steel and it is easily machined, cast, drawn and extruded. Aluminium atoms are arranged in a cubic structure. Aluminium has an energy of approximately 200 mJ/m2. Aluminium is a thermal and electrical conductor, having 59% the conductivity of copper. Aluminium is capable of superconductivity, with a critical temperature of 1.2 kelvin. Aluminium is the most common material for the fabrication of superconducting qubits, the strongest aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is reduced by aqueous salts, particularly in the presence of dissimilar metals. In highly acidic solutions, aluminium reacts with water to form hydrogen, primarily because it is corroded by dissolved chlorides, such as common sodium chloride, household plumbing is never made from aluminium
5.
Carbon fiber reinforced polymer
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Carbon fiber reinforced polymer, carbon fiber reinforced plastic or carbon fiber reinforced thermoplastic, is an extremely strong and light fiber-reinforced plastic which contains carbon fibers. The spelling fibre is common in British Commonwealth countries, the binding polymer is often a thermoset resin such as epoxy, but other thermoset or thermoplastic polymers, such as polyester, vinyl ester or nylon, are sometimes used. The composite may contain other fibers, such as an aramid, aluminium, ultra-high-molecular-weight polyethylene or glass fibers, the properties of the final CFRP product can also be affected by the type of additives introduced to the binding matrix. The most frequent additive is silica, but other such as rubber. The material is referred to as graphite-reinforced polymer or graphite fiber-reinforced polymer. In product advertisements, it is referred to simply as graphite fiber for short. In this case the composite consists of two parts, a matrix and a reinforcement, in CFRP the reinforcement is carbon fiber, which provides the strength. The matrix is usually a resin, such as epoxy. Because CFRP consists of two elements, the material properties depend on these two elements. The reinforcement will give the CFRP its strength and rigidity, measured by stress, unlike isotropic materials like steel and aluminum, CFRP has directional strength properties. The properties of CFRP depend on the layouts of the carbon fiber, the following equation, E c = V m E m + V f E f is valid for composite materials with the fibers oriented in the direction of the applied load. Typical epoxy-based CFRPs exhibit virtually no plasticity, with less than 0. 5% strain to failure, although CFRPs with epoxy have high strength and elastic modulus, the brittle fracture mechanics present unique challenges to engineers in failure detection since failure occurs catastrophically. As such, recent efforts to toughen CFRPs include modifying the existing epoxy material, One such material with high promise is PEEK, which exhibits an order of magnitude greater toughness with similar elastic modulus and tensile strength. However, PEEK is much more difficult to process and more expensive, despite its high initial strength-to-weight ratio, a design limitation of CFRP is its lack of a definable fatigue endurance limit. This means, theoretically, that stress cycle failure cannot be ruled out, environmental effects such as temperature and humidity can have profound effects on the polymer-based composites, including most CFRPs. While the carbon fibers themselves are not affected by the moisture diffusing into the material, the carbon fibers can cause galvanic corrosion when CRP parts are attached to aluminum. The primary element of CFRP is a filament, this is produced from a precursor polymer such as polyacrylonitrile, rayon. Precursor compositions and mechanical processes used during spinning filament yarns may vary among manufacturers, after drawing or spinning, the polymer filament yarns are then heated to drive off non-carbon atoms, producing the final carbon fiber
6.
Image stabilization
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Image stabilization is a family of techniques used to reduce blurring associated with the motion of a camera or other imaging device during exposure. Generally, it compensates for pan and tilt of the imaging device and it is used in image-stabilized binoculars, still and video cameras, astronomical telescopes, and also smartphones, mainly the high-end. With still cameras, camera shake is particularly problematic at slow speeds or with long focal length lenses. With video cameras, camera shake causes visible frame-to-frame jitter in the recorded video, in astronomy, the problem of lens-shake is added to by variations in the atmosphere over time, which will cause the apparent positions of objects to change. In photography, image stabilization can often permit the use of shutter speeds 2–4.5 stops slower, for example, at a focal length of 125 mm on a 35 mm camera, vibration or camera shake could affect sharpness if the shutter speed was slower than 1/125 second. The sharpness obtainable at a speed can increase dramatically. When calculating the effective length, it is important to take into account the image format a camera uses. For example, many digital SLR cameras use a sensor that is 2/3, 5/8. This means that the 35 mm frame is 1.5,1.6, the latter values are referred to as the crop factor, field-of-view crop factor, focal-length multiplier, or format factor. On a 2x crop factor camera, for instance, a 50 mm lens produces the field of view as a 100 mm lens used on a 35 mm film camera. However, image stabilization does not prevent motion blur caused by the movement of the subject or by extreme movements of the camera, Image stabilization is only designed for and capable of reducing blur that results from normal, minute shaking of a lens due to hand-held shooting. Some lenses and camera bodies include a secondary panning mode or a more aggressive active mode, image-stabilization features can also be a benefit in astrophotography, when the camera is technically—but not effectively—fixed in place. The Pentax K-5 and K-r can use their sensor-shift capability to reduce star trails in reasonable exposure times, in effect, the stabilization compensates for the Earths motion, not the cameras. There are two types of implementation - lens-based, or body-based stabilization and these refer to where the stabilizing system is located. Both have their advantages and disadvantages, an optical image stabilizer, often abbreviated OIS, IS, or OS, is a mechanism used in a still camera or video camera that stabilizes the recorded image by varying the optical path to the sensor. This technology is implemented in the lens itself, as distinct from In Body Image Stabilization, the key element of all optical stabilization systems is that they stabilize the image projected on the sensor before the sensor converts the image into digital information. In Nikon and Canons implementation, it works by using a lens element that is moved orthogonally to the optical axis of the lens using electromagnets. Vibration is detected using two piezoelectric angular velocity sensors, one to detect movement and the other to detect vertical movement
7.
Sharpness (visual)
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In photography, the term acutance describes a subjective perception of sharpness that is related to the edge contrast of an image. Acutance is related to the amplitude of the derivative of brightness with respect to space, due to the nature of the human visual system, an image with higher acutance appears sharper even though an increase in acutance does not increase real resolution. Historically, acutance was enhanced chemically during development of a negative, in the example image, two light gray lines were drawn on a gray background. As the transition is instantaneous, the line is as sharp as can be represented at this resolution, acutance in the left line was artificially increased by adding a one-pixel-wide darker border on the outside of the line and a one-pixel-wide brighter border on the inside of the line. The actual sharpness of the image is unchanged, but the apparent sharpness is increased because of the greater acutance. In this somewhat overdone example most viewers will also be able to see the borders separately from the line, several image processing techniques, such as unsharp masking, can increase the acutance in real images. Low-pass filtering and resampling often cause overshoot, which increases acutance, but can also reduce absolute gradient, filtering and resampling can also cause clipping and ringing artifacts. An example is bicubic interpolation, widely used in processing for resizing images. Thus the acutance of an image is a vector field, coarse grain or noise can, like sharpening filters, increase acutance, hence increasing the perception of sharpness, even though they degrade the signal-to-noise ratio
8.
C-stand
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In film production, a C-stand is primarily used to position light modifiers, such as silks, nets, or flags, in front of light sources. The stand is constructed of metal and consists of a collapsible base, in addition, a C-stand includes a gobo head and a gobo arm, which provide the ability to articulate a light modifier without moving the stand itself. The legs of C stands are designed to be nested, so many stands can be placed around a light source, the term C-stand comes from the early history of lighting equipment where a popular sized sun reflector was 100 inches square or century. Today the term C-stand is a name for the grip stand made by Matthews studio equipment and has been copied by other manufacturers. A secondary use of C-stands is to position smaller light fixtures, a typical use would be to offset a backlight from the stand column, so that the stand itself can be placed out of shot, while the backlight hovers somewhere above the top edge of frame. In recent years, C-stands have found a new use, supporting the brackets used for balancing Steadicam camera sleds, due to the off-center weight distribution in this practice, it is necessary to use sandbags to add weight to the C-stand leg opposite the camera sled. A C-stand is sometimes referred to as a grip stand, while the grip department always carries C stands, sometimes the electric department may as well, for use well as lights that dont mount onto baby or junior stands, such as kinos. A baby C-stand is only 20 inches at its shortest height and it is nicknamed a Gary Coleman or a Billy Barty stand in the US. In the UK a short flag stand with legs is called a shotgun flag stand. A C-stand with a base is called a C-stand with a turtle base. The opening at the top of the turtle base accepts the base of c-stand upright or a junior pin, turtle bases are great for setting up a light very low to the ground. A C-stand with an upper most leg which is moveable on the axis is called a Stair Leg C-stand as the unit can be placed on a stairway. Also called a Rocky Mountain leg
