Cameras and Photographs [2]
Webpages concerning "Cameras and Photographs [2]"
|
The contents has been generating using technology developed by scientec.
Wikipedia-Article "Cameras"
- This is the article about the photographing device. For other uses, see CAMERA.
A camera is a device used to take pictures (usually photographs), either singly or in sequence, with or without sound recording, such as with video cameras. A camera that takes pictures singly is sometimes called a photo camera to distinguish it from a video camera. The name is derived from camera obscura, Latin for "dark chamber", an early mechanism for projecting images in which an entire room functioned much as the internal workings of a modern photographic camera, except there was no way at this time to record the image short of manually tracing it. Cameras may work with the visual spectrum or other portions of the electromagnetic spectrum.
Contents |
Description
Every camera consists of some kind of enclosed chamber, with an opening or aperture at one end for light to enter, and a recording or viewing surface for capturing the light at the other end. This diameter of the aperture is often controlled by an diaphragm mechanism, but some cameras have a fixed-size aperture.
While the size of the aperture and the brightness of the scene control the amount of light that enters the camera during photographing, the shutter controls the length of time that the light hits the recording surface. For example, in lower light situations, the shutter speed should be slower (longer time spent open) to allow the film to capture what little light is present.
There are various ways of focusing a camera accurately. The simplest cameras have fixed focus and use a small aperture and wide-angle lens to ensure that everything within a certain range of distance from the lens (usually around 3 metres (10 feet) to infinity) is in reasonable focus. This is usually the kind found on one-use cameras and other cheap cameras. The camera can also have a limited focusing range or scale-focus that is indicated on the camera body. The user will guess or calculate the distance to the subject and adjust the focus accordingly. On some cameras this is indicated by symbols (head-and-shoulders; two people standing upright; one tree; mountains).
Rangefinder cameras focus by means of a coupled parallax unit on top of the camera. Single-lens reflex cameras allow the photographer to determine the focus and composition visually using the objective lens and a moving mirror to project the image onto a ground glass or plastic micro-prism screen. Twin-lens reflex cameras use an objective lens and a focusing lens unit (usually identical to the objective lens) in a parallel body for composition and focusing. View cameras use a ground glass screen which is removed and replaced by either a photographic plate or a reusable holder containing sheet film before exposure.
Traditional cameras capture light onto photographic film or photographic plate. Video and digital cameras use electronics, usually a charge coupled device (CCD) or sometimes a CMOS sensor to capture images which can be transferred or stored in tape or computer memory inside the camera for later playback or processing.
Cameras that capture many images in sequence are known as movie cameras or as ciné cameras in Europe; those designed for single images are still cameras. However these categories overlap, as still cameras are often used to capture moving images in special effects work and modern digital cameras are often able to trivially switch between still and motion recording modes. A video camera is a category of movie camera which stores images onto magnetic tape (either using analogue or digital technology).
Stereo camera can take photographs that appear "three-dimensional" by taking two different photographs which are combined to create the illusion of depth in the composite image. Stereo cameras for making 3D prints or slides have two lenses side by side. Stereo cameras for making lenticular prints have 3, 4, 5, or even more lenses.
Some film cameras feature date imprinting devices that can print a date on the negative itself.
History
- Main article: History of the camera
The first permanent photograph was made in 1826 by Joseph Nicéphore Niépce using a sliding wooden box camera made by Charles and Vincent Chevalier in Paris. However, while this was the birth of photography, the camera itself can be traced back much further. Photographic cameras were a development of the camera obscura, a device dating back at least to the 11th century which uses a pinhole or lens to project an image of the scene outside onto a viewing surface. Before the invention of photography, there was no way to preserve the images produced by these cameras apart from manually tracing them.
The first camera that was small and portable enough to be practical for photography was built by Johann Zahn in 1685, though it would be almost 150 years before technology caught up to the point where this was possible. Early photographic cameras were essentially similar to Zahn's model, though usually with the addition of sliding boxes for focusing. Before each exposure a sensitized plate would be inserted in front of the viewing screen to record the image. Jacques Daguerre's popular daguerreotype process utilized copper plates, while the calotype process invented by William Talbot recorded images on paper.
The development of the collodion wet plate process by Frederick Scott Archer in 1850 cut exposure times dramatically, but required photographers to prepare and develop their glass plates on the spot, usually in a mobile darkroom. Despite their complexity, the wet-plate ambrotype and tintype processes were in widespread use in the latter half of the 19th century. Wet plate cameras were little different from previous designs, though there were some models (such as the sophisticate Dubroni of 1864) where the sensitizing and developing of the plates could be carried out inside the camera itself rather than in a separate darkroom. Other cameras were fitted with multiple lenses for making making cartes de visite. It was during the wet plate era that the use of bellows for focusing became widespread.
See also
Camera brands
- Agfa
- ARCA-Swiss
- Agilux
- Balda
- Bolex
- Braun
- Bronica
- Burke & James
- Cambo
- Canon
- Casio
- Contax
- Corfield
- Coronet
- Ebony
- FED
- Fujifilm
- Graflex
- Hasselblad
- Hewlett Packard
- Holga
- Ilford
- Kodak
- Konica
- Leica
- Linhof
- Lomo
- Minolta
- Mamiya
- Minox
- MPP
- Mustek
- Newman & Guardia
- Nikon
- Olympus
- Osaka
- Panasonic
- Pentax
- Polaroid
- Praktica
- Reid
- Ricoh
- Rollei
- Sigma Corporation
- Sony
- Vivitar
- Voigtländer
- Wisner
- Wray
- Yashica
- Zeiss
- Zenit
- Zone VI
- Zorki
External links
Wikipedia-Article "Photographs [2]"
- Photo redirects here. For the French magazine, see Photo (magazine).
A photograph (often shortened to photo) is an image (or a representation of that on e.g. paper) created by collecting and focusing reflected electromagnetic radiation. The most common photographs are those created of reflected visible wavelengths, producing permanent records of what the human eye can see.
Most photographs are made with a camera, which focuses the light onto either photographic film or a CCD or CMOS image sensor. Photographs can also be made by placing objects on photosensitive paper and exposing it to light (the result is often called a photogram) or by placing objects on the platen of a flatbed scanner (see scanner art).
History and special effects
Most traditional photographs are produced with a two-step chemical process. In the two-step process, the film holds a negative image (colours and lights/darks are inverted), which is then transferred onto photographic paper as a positive image. Another widely used film is the positive film used for producing transparencies, usually mounted in cardboard or plastic frames called slides. Slides are widely used by professionals mostly due to their sharpness and accuracy of colour rendition. Most photographs published in magazines are still originally taken on colour transparency film.
Originally almost all photographs were black and white. Although methods for developing color photos were available as early as the late 19th century, they did not become widely available until the 1940s or 50s, and even in until the 1960s most photographs were taken in black and white. Since then, color photography has dominated popular photography, although the black and white format remains popular for amateur photographers and artists. Black and white film is considerably easier to develop than colour.
Panoramic format Images can be taken by using special cameras like the Hasselblad Xpan on standard film. Since the 1990s, panoramic photos have been relatively easy for the general population to take on Advanced Photo System film. APS was developed by several of the major film manufacturers to provide a "smart" film with different formats and computerized options available, though APS panoramas were created using a mask in panorama-capable cameras, far less desirable than a true panoramic camera which achieves its effect through wider film format. As with many past ideas in consumer film formats, APS has become less popular and will be discontinued in the near future.
Digital photos can be stored in various file formats, of which JPEG is one of the most popular. Many other graphic formats are used, including TIFF, PNG, GIF, and RAW.
See also
