A video camera is a camera used for electronic motion picture acquisition, initially developed for the television industry but now common in other applications as well. Video cameras are used primarily in two modes. The first, characteristic of much early broadcasting, is live television, where the camera feeds real time images directly to a screen for immediate observation. A few cameras still serve live television production, but most live connections are for security, military/tactical, and industrial operations where surreptitious or remote viewing is required. In the second mode the images are recorded to a storage device for archiving or further processing; for many years, videotape was the primary format used for this purpose, but was gradually supplanted by optical disc, hard disk, and then flash memory. Recorded video is used in television production, and more often surveillance and monitoring tasks in which unattended recording of a situation is required for later analysis.
Types and uses
Modern video cameras have numerous designs and use:
Professional video cameras, such as those used in television production, maybe television studio-based or mobile in the case of an electronic field production. Such cameras generally offer extremely fine-grained manual control for the camera operator, often to the exclusion of automated operation. They usually use three sensors to separately record red, green and blue.
Closed-circuit television generally uses pan–tilt–zoom cameras, for security, 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 settings are often meant for use in environments that are normally inaccessible or uncomfortable for humans, and are therefore hardened for such hostile environments.
Webcams are video cameras that stream a live video feed to a computer.
The earliest video cameras were based on the mechanical Nipkow disk and used in experimental broadcasts through the 1910s–1930s. All-electronic designs based on the video camera tube, such as Vladimir Zworykin's Iconoscope and Philo Farnsworth's image dissector, supplanted the Nipkow system by the 1930s. These remained in wide use until the 1980s, when cameras based on solid-stateimage sensors such as the charge-coupled device and CMOSactive-pixel sensor eliminated common problems with tube technologies such as image burn-in and made digital video workflow practical. The basis for solid-state image sensors is metal-oxide-semiconductor technology, which originates from the invention of the MOSFET at Bell Labs in 1959. This led to the development of semiconductor image sensors, including the CCD and later the CMOS active-pixel sensor. The first semiconductor image sensor was the charge-coupled device, invented at Bell Labs in 1969, based on MOS capacitor technology. The NMOS active-pixel sensor was later invented at Olympus in 1985, which led to the development of the CMOS active-pixel sensor at NASA's Jet Propulsion Laboratory in 1993. Practical digital video cameras were also enabled by advances in video compression, due to the impractically high memory and bandwidth requirements of uncompressed video. The most important compression algorithm in this regard is the discrete cosine transform, a lossy compression technique that was first proposed in 1972. Practical digital video cameras were enabled by DCT-based video compression standards, including the H.26x and MPEGvideo coding standards introduced from 1988 onwards. The transition to digital television gave a boost to digital video cameras. By the early 21st century, most video cameras were digital cameras. With the advent of digital video capture, the distinction between professional video cameras and movie cameras has disappeared as the intermittent mechanism has become the same. Nowadays, mid-range cameras exclusively used for television and other work are termed professional video cameras.
