   #copyright

Photography

2007 Schools Wikipedia Selection. Related subjects: Art; Recreation

   Photography [fә'tɑgrәfi:],[foʊ'tɑgrәfi:] is the process of recording
   pictures by means of capturing light on a light-sensitive medium, such
   as a sensor or film. Light patterns reflected or emitted from objects
   expose a sensitive chemical or electronic medium during a timed
   exposure, usually through a photographic lens in a device known as a
   camera that also stores the resulting information chemically or
   electronically.
   Lens and mounting of a large-format camera
   Lens and mounting of a large-format camera

   The word comes from the Greek words φως phos ("light"), and γραφίς
   graphis ("stylus", "paintbrush") or γραφή graphê ("representation by
   means of lines" or "drawing"), together meaning "drawing with light."
   Traditionally, the product of photography has been called a photograph,
   commonly abbreviated photo.

Photographic cameras

   The camera or camera obscura is the image-forming device, and
   photographic film or a digital storage card is the recording medium.

   Photographers control the camera and lens to "expose" the light
   recording material (usually film or a charge-coupled device; a
   complementary metal-oxide-semiconductor may also be used) to the
   required amount of light. After processing, this produces an image.

   The controls usually include but are not limited to the following:
     * Focus of the lens
     * Aperture of the lens – adjustment of the iris, measured as
       f-number, which controls the amount of light entering the lens.
       Aperture also has an effect on focus and depth of field, namely,
       the smaller the opening [aperture], the less light but the greater
       the depth of field--that is, the greater the range within which
       objects appear to be sharply focused.
     * Shutter speed – adjustment of the speed (often expressed either as
       fractions of seconds or as an angle, with mechanical shutters) of
       the shutter to control the amount of time during which the imaging
       medium is exposed to light for each exposure. Shutter speed may be
       used to control the amount of light striking the image plane;
       'faster' shutter speeds (that is, those of shorter duration)
       decrease both the amount of light and the amount of image blurring
       from subject motion or camera motion.
     * White balance – on digital cameras, electronic compensation for the
       colour temperature associated with a given set of lighting
       conditions, ensuring that white light is registered as such on the
       imaging chip and therefore that the colors in the frame will appear
       natural. On mechanical, film-based cameras, this function is served
       by the operator's choice of film stock. In addition to using white
       balance to register natural coloration of the image, photographers
       may employ white balance to aesthetic end, for example white
       balancing to a blue object in order to obtain a warm colour
       temperature.
     * Metering – measurement of exposure at a midtone so that highlights
       and shadows are exposed according to the photographer's wishes.
       Many modern cameras feature this ability, though it is
       traditionally accomplished with the use of a separate light
       metering device.
     * ISO speed – traditionally used to set the film speed of the
       selected film on film cameras, ISO speeds are employed on modern
       digital cameras as an indication of the system's gain from light to
       numerical output and to control the automatic exposure system. A
       correct combination of ISO speed, aperture, and shutter speed leads
       to an image that is neither too dark nor too light.
     * Auto-focus point – on some cameras, the selection of a point in the
       imaging frame upon which the auto-focus system will attempt to
       focus. Many SLR cameras feature multiple auto-focus points in the
       viewfinder.

   Many other elements of the imaging device itself may have a pronounced
   effect on the quality and/or aesthetic effect of a given photograph;
   among them are:
     * Focal length and type of lens ( telephoto, macro, wide angle, or
       zoom)
     * Filters or scrims placed between the subject and the light
       recording material, either in front of or behind the lens
     * Inherent sensitivity of the medium to light intensity and
       colour/wavelengths.
     * The nature of the light recording material, for example its
       resolution as measured in pixels or grains of silver halide.

   Camera controls are inter-related, the total amount of light reaching
   the film plane (the "exposure") changes with the duration of exposure,
   aperture of the lens, and focal length of the lens (which changes as
   the lens is zoomed). Changing any of these controls alters the
   exposure. Many cameras may be set to adjust most or all of these
   controls automatically. This automatic functionality is useful in many
   situations, and in most situations to occasional photographers.

   The duration of an exposure is referred to as shutter speed, often even
   in cameras that don't have a physical shutter, and is typically
   measured in fractions of a second. Aperture is expressed by an f-number
   or f-stop (derived from focal ratio), which is proportional to the
   ratio of the focal length to the diameter of the aperture. If the
   f-number is decreased by a factor of \sqrt 2 , the aperture diameter is
   increased by the same factor, and its area is increased by a factor of
   2. The f-stops that might be found on a typical lens include 2.8, 4,
   5.6, 8, 11, 16, 22, 32, where going up "one stop" doubles the amount of
   light reaching the film, and stopping down one stop halves the amount
   of light.

   Exposures can be achieved through various combinations of shutter speed
   and aperture. For example, f/8 at 1/125th of a second and f/4 at
   1/500th of a second yield the same amount of light. The chosen
   combination has an impact on the final result. In addition to the
   subject or camera movement that might vary depending on the shutter
   speed, the aperture (and focal length of the lens) determine the depth
   of field, which refers to the range of distances from the lens that
   will be in focus. For example, using a long lens and a large aperture
   (f/2.8, for example), a subject's eyes might be in sharp focus, but not
   the tip of the nose. With a smaller aperture (f/22), or a shorter lens,
   both the subject's eyes and nose can be in focus. With very small
   apertures, such as pinholes, a wide range of distance can be brought
   into focus.

   Image capture is only part of the image forming process. Regardless of
   material, some process must be employed to render the latent image
   captured by the camera into the final photographic work. This process
   consists of two steps, development, and printing.

   During the printing process, modifications can be made to the print by
   several controls. Many of these controls are similar to controls during
   image capture, while some are exclusive to the printing process. Most
   controls have equivalent digital concepts, but some create different
   effects. For example, dodging and burning controls are different
   between digital and film processes. Other printing modifications
   include:
     * Chemicals and process used during film development
     * Duration of exposure — equivalent to shutter speed
     * Printing aperture — equivalent to aperture, but has no effect on
       depth of field
     * Contrast
     * Dodging — reduces exposure of certain print areas, resulting in a
       lighter areas
     * Burning — increases exposure of certain areas, resulting in darker
       areas
     * Paper quality — glossy, matte, etc

Uses of photography

   Photography gained the interest of many scientists and artists from its
   inception. Scientists have used photography to record and study
   movements, such as Eadweard Muybridge's study of human and animal
   locomotion in 1887. Artists are equally interested by these aspects but
   also try to explore avenues other than the photo-mechanical
   representation of reality, such as the pictorialist movement. Military,
   police and security forces use photography for surveillance,
   recognition and data storage. Photography is used to preserve memories
   of favorites and as a source of entertainment.

History of photography

   Nicéphore Niépce's earliest surviving photograph, c. 1826. This image
   required an eight-hour exposure, which resulted in sunlight being
   visible on both sides of the buildings.
   Nicéphore Niépce's earliest surviving photograph, c. 1826. This image
   required an eight-hour exposure, which resulted in sunlight being
   visible on both sides of the buildings.

   Modern photography can be traced to the 1820s with the development of
   chemical photography. The first permanent photograph was an image
   produced in 1826 by the French inventor Nicéphore Niépce. However, the
   picture took eight hours to expose, so he went about trying to find a
   new process. Working in conjunction with Louis Daguerre, they
   experimented with silver compounds based on a Johann Heinrich Schultz
   discovery in 1724 that a silver and chalk mixture darkens when exposed
   to light. Niépce died in 1833, but Daguerre continued the work,
   eventually culminating with the development of the daguerreotype in
   1839.

   Meanwhile, Hercules Florence had already created a very similar process
   in 1832, naming it Photographie, and William Fox Talbot had earlier
   discovered another means to fix a silver process image but had kept it
   secret. After reading about Daguerre's invention, Talbot refined his
   process so that it might be fast enough to take photographs of people.
   By 1840, Talbot had invented the calotype process, which creates
   negative images. John Herschel made many contributions to the new
   methods. He invented the cyanotype process, now familiar as the
   "blueprint". He was the first to use the terms "photography",
   "negative" and "positive". He discovered sodium thiosulphate solution
   to be a solvent of silver halides in 1819, and informed Talbot and
   Daguerre of his discovery in 1839 that it could be used to "fix"
   pictures and make them permanent. He made the first glass negative in
   late 1839.

   Many advances in photographic glass plates and printing were made in
   through the nineteenth century. In 1884, George Eastman developed the
   technology of film to replace photographic plates, leading to the
   technology used by film cameras today.

Photography types

Black-and-white photography

   All photography was originally monochrome, or black-and-white. Even
   after color film was readily available, black-and-white photography
   continued to dominate for decades, due to its lower cost and its
   "classic" photographic look. In modern times, black-and-white has
   mostly become a minority art form, and most photography has become
   colour photography.

Colour photography

   Colour photography was explored throughout the late 1800s and early
   1900s. Early experiments in color could not fix the photograph and
   prevent the color from fading. The first permanent colour photo was
   taken in 1861 by the physicist James Clerk Maxwell.
   Early color photograph taken by Prokudin-Gorskii (1915)
   Early colour photograph taken by Prokudin-Gorskii (1915)

   One of the early methods of taking color photos was to use three
   cameras. Each camera would have a colour filter in front of the lens.
   This technique provides the photographer with the three basic channels
   required to recreate a colour image in a darkroom or processing plant.
   Russian photographer Sergei Mikhailovich Prokudin-Gorskii developed
   another technique, with three colour plates taken in quick succession.

   Practical application of the technique was held back by the very
   limited colour response of early film; however, in the early 1900s,
   following the work of photo-chemists such as H. W. Vogel, emulsions
   with adequate sensitivity to green and red light at last became
   available.

   The first colour plate, Autochrome, invented by the French Lumière
   brothers, reached the market in 1907. It was based on a 'screen-plate'
   filter made of dyed dots of potato starch, and was the only colour film
   on the market until German Agfa introduced the similar Agfacolor in
   1932. In 1935, American Kodak introduced the first modern ('integrated
   tri-pack') colour film, Kodachrome, based on three colored emulsions.
   This was followed in 1936 by Agfa's Agfacolor Neue. Unlike the
   Kodachrome tri-pack process the color couplers in Agfacolor Neue were
   integral with the emulsion layers, which greatly simplified the film
   processing. Most modern colour films, except Kodachrome, are based on
   the Agfacolor Neue technology. Instant colour film was introduced by
   Polaroid in 1963.

   As an interesting side note, the inventors of Kodachrome, Leopold
   Mannes and Leopold Godowsky, Jr. were both accomplished musicians.
   Godowsky was the brother-in-law of George Gershwin and his father was
   Leopold Godowsky, one of the world's greatest pianists.

   Colour photography may form images as a positive transparency, intended
   for use in a slide projector or as color negatives, intended for use in
   creating positive color enlargements on specially coated paper. The
   latter is now the most common form of film (non-digital) colour
   photography owing to the introduction of automated photoprinting
   equipment.

Digital photography

   Nikon digital camera and scanner, which converts film images to digital
   Nikon digital camera and scanner, which converts film images to digital

   Traditional photography burdened photographers working at remote
   locations without easy access to processing facilities, and competition
   from television pressured photographers to deliver images to newspapers
   with greater speed. Photo journalists at remote locations often carried
   miniature photo labs and a means of transmitting images through
   telephone lines. In 1981, Sony unveiled the first consumer camera to
   use a charge-coupled device for imaging, eliminating the need for film:
   the Sony Mavica. While the Mavica saved images to disk, the images were
   displayed on television, and the camera was not fully digital. In 1990,
   Kodak unveiled the DCS 100, the first commercially available digital
   camera. Although its high cost precluded uses other than
   photojournalism and professional photography, commercial digital
   photography was born.

   Digital imaging uses an electronic image sensor to record the image as
   a set of electronic data rather than as chemical changes on film. The
   primary difference between digital and chemical photography is that
   analog photography resists manipulation because it involves film,
   optics and photographic paper, while digital imaging is a highly
   manipulative medium. This difference allows for a degree of image
   post-processing that is comparatively difficult in film-based
   photography, permitting different communicative potentials and
   applications.

   Digital imaging is rapidly replacing film photography in consumer and
   professional markets. Digital point-and-shoot cameras have become
   widespread consumer products, outselling film cameras, and including
   new features such as video and audio recording. Kodak announced in
   January 2004 that it would no longer produce reloadable 35 mm cameras
   after the end of that year. This was interpreted as a sign of the end
   of film photography. However, Kodak was at that time a minor player in
   the reloadable film cameras market. In January 2006, Nikon followed
   suit and announced that they will stop the production of all but two
   models of their film cameras: the low-end Nikon FM10, and the high-end
   Nikon F6. On May 25, 2006, Canon announced they will stop developing
   new film SLR cameras.

   Because photography is popularly synonymous with truth ("The camera
   doesn't lie."), digital imaging has raised many ethical concerns. Many
   photojournalists have declared they will not crop their pictures, or
   are forbidden from combining elements of multiple photos to make
   "illustrations," passing them as real photographs. Many courts will not
   accept digital images as evidence because of their inherently
   manipulative nature. Today's technology has made picture editing
   relatively easy for even the novice photographer.

Photography styles

Commercial photography

   The commercial photographic world can be broken down to:
     * Advertising photography: photographs made to illustrate a service
       or product. These images are generally done with an advertising
       agency, design firm or with an in-house corporate design team.
     * Fashion and glamour photography: This type of photography usually
       incorporates models. Fashion photography emphasizes the clothes or
       product, glamour emphasizes the model. Glamour photography is
       popular in advertising and in men's magazines. Models in glamour
       photography may be nude, but this is not always the case.
     * Still life photography usually depicts inanimate subject matter,
       typically commonplace objects which may be either natural or
       man-made.
     * Editorial photography: photographs made to illustrate a story or
       idea within the context of a magazine. These are usually assigned
       by the magazine.
     * Photojournalism: this can be considered a subset of editorial
       photography. Photographs made in this context are accepted as a
       truthful documentation of a news story.
     * Portrait and wedding photography: photographs made and sold
       directly to the end user of the images.
     * Fine art photography: photographs made to fulfill a vision, and
       reproduced to be sold directly to the customer.
     * Landscape photography: photographs of different locations made to
       be sold to tourists as postcards

   The market for photographic services demonstrates the aphorism "one
   picture is worth a thousand words," which has an interesting basis in
   the history of photography. Magazines and newspapers, companies putting
   up Web sites, advertising agencies and other groups pay for
   photography.

   Many people take photographs for self-fulfillment or for commercial
   purposes. Organizations with a budget and a need for photography have
   several options: they can assign a member of the organization or hire
   someone to shoot exactly what thay want, run a public competition, or
   obtain rights to stock photographs either through traditional stock
   giants, such as Getty Images, or through smaller microstock agencies,
   such as Fotolia.

Photography as an art form

   Manual shutter control and exposure settings can achieve unusual
   results
   Manual shutter control and exposure settings can achieve unusual
   results
   Classic Alfred Stieglitz photograph, The Steerage shows unique
   aesthetic of black and white photos.
   Classic Alfred Stieglitz photograph, The Steerage shows unique
   aesthetic of black and white photos.

   During the twentieth century, both fine art photography and documentary
   photography became accepted by the English-speaking art world and the
   gallery system. In the United States, a handful of photographers spent
   their lives advocating for photography as a fine art. Alfred Stieglitz,
   Edward Steichen, John Szarkowski, and Edward Weston the most prominent
   among them.

   At first, fine art photographers tried to imitate painting styles. This
   movement is called Pictorialism, often using soft focus for a dreamy,
   'romantic' look. In reaction to that, Weston, Ansel Adams, and others
   formed the f/64 Group to advocate 'straight photography', the
   photograph as a (sharply focused) thing in itself and not an imitation
   of something else.

   The aesthetics of photography is a matter that continues to be
   discussed regularly, especially in artistic circles. Many artists
   argued that photography was the mechanical reproduction of an image. If
   photography is authentically art, then photography in the context of
   art would need redefinition, such as determining what component of a
   photograph makes it beautiful to the viewer. The controversy began with
   the earliest images "written with light": Nicéphore Niépce, Louis
   Daguerre, and others among the very earliest photographers were met
   with acclaim, but some questioned if it met the definitions and
   purposes of art.

   Clive Bell in his classic essay Art states that only "significant form"
   can distinguish art from what is not art.

     There must be some one quality without which a work of art cannot
     exist; possessing which, in the least degree, no work is altogether
     worthless. What is this quality? What quality is shared by all
     objects that provoke our aesthetic emotions? What quality is common
     to Sta. Sophia and the windows at Chartres, Mexican sculpture, a
     Persian bowl, Chinese carpets, Giotto's frescoes at Padua, and the
     masterpieces of Poussin, Piero della Francesca, and Cezanne? Only
     one answer seems possible - significant form. In each, lines and
     colors combined in a particular way, certain forms and relations of
     forms, stir our aesthetic emotions.

     –

Technical photography

   The camera has a long and distinguished history as a means of recording
   phenomena from the first use by Daguerre and Fox-Talbot, such as
   astronomical events (eclipses for example) and small creatures when the
   camera was attached to the eyepiece of microscopes (in
   photomicroscopy). The camera also proved useful in recording crime
   scenes and the scenes of accidents, one of the first uses being at the
   scene of the Tay Rail Bridge disaster of 1879. The set of accident
   photographs was used in the subsequent court of inquiry so that
   witnesses could identify pieces of the wreckage, and the technique is
   now commonplace in courts of law.

Other photographic image forming techniques

   Besides the camera, other methods of forming images with light are
   available. For instance, a photocopy or xerography machine forms
   permanent images but uses the transfer of static electrical charges
   rather than photographic film, hence the term electrophotography.
   Rayographs published by Man Ray and others are images produced by the
   shadows of objects cast on the photographic paper, without the use of a
   camera. Objects can also be placed directly on the glass of an image
   scanner to produce digital pictures.
   Retrieved from " http://en.wikipedia.org/wiki/Photography"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
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