Video camera


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Video camera

  1. 1. A video camera is a camera used for electronic motion picture acquisition, initiallydeveloped by the television industry but now common in other applications as well. Theearliest video cameras were those of John Logie Baird, based on the electromechanicalNipkow disk and used by the BBC in experimental broadcasts through the 1930s. All-electronic designs based on the cathode ray tube, such as Vladimir Zworykins Iconoscopeand Philo T. Farnsworths Image dissector, supplanted the Baird system by the 1940s andremained in wide use until the 1980s, when cameras based on solid-state image sensorssuch as CCDs (and later CMOS active pixel sensors) eliminated common problems with tubetechnologies such as image burn-in and made digital video workflow practical.Video cameras are used primarily in two modes. The first, characteristic of much earlybroadcasting, is live television, where the camera feeds real time images directly to a screenfor immediate observation. A few cameras still serve live television production, but most liveconnections are for security, military/tactical, and industrial operations where surreptitiousor remote viewing is required. In the second mode the images are recorded to a storagedevice for archiving or further processing; for many years, videotape was the primary formatused for this purpose, but optical disc media, hard disk, and flash memory in tapelesscamcorders are all increasingly used. Recorded video is used in television and filmproduction and more often surveillance and monitoring tasks where unattended recordingof a situation is required for later analysis.Modern video cameras have numerous designs and uses, not all of which resemble the earlytelevision cameras.Professional video cameras, such as those used in television production andsometimes filmmaking in digital cinema; these may be television studio-based or mobile inthe case of an electronic field production (EFP). Such cameras generally offer extremely fine-grained manual control for the camera operator, often to the exclusion of automatedoperation. Camcorders, which combine a camera and a VCR or other recording device in oneunit; these are mobile, and are widely used for television production, home movies,electronic news gathering (ENG) (including citizen journalism), and similar applications.Some digital ones are Pocket video camera.Closed-circuit television (CCTV) generally use pan tilt zoom cameras (PTZ), forsecurity, surveillance, and/or monitoring purposes. Such cameras are designed to be small,easily hidden, and able to operate unattended; those used in industrial or scientific settingsare often meant for use in environments that are normally inaccessible or uncomfortable forhumans, and are therefore hardened for such hostile environments (e.g. radiation, high)heat, or toxic chemical exposure.Webcams are video cameras which stream a live video feed to a computer. Largervideo cameras (especially camcorders and CCTV cameras) can be similarly used, though theymay need an analog-to-digital converter in order to store the output on a computer ordigital video recorder or send it to a wider network.
  2. 2. Most 21st century video cameras are digital cameras which converts the signaldirectly to a digital output; such cameras are often small, even smaller than CCTV securitycameras, and are often used as webcams or optimized for still-camera use. The majority areincorporated directly into computer or communications hardware, particularly mobilephones, though analog video equipment remains in use.Special systems, like those used for scientific research, e.g. on board a satellite or aspace probe, or in artificial intelligence and robotics research. Such cameras are often tunedfor non-visible radiation for Infrared photography (for night vision and heat sensing) or X-ray(for medical and video astronomy use).