Video camera
Encyclopedia
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
used for electronic motion picture acquisition, initially developed by the television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
industry but now common in other applications as well. The earliest video cameras were those of John Logie Baird
John Logie Baird
John Logie Baird FRSE was a Scottish engineer and inventor of the world's first practical, publicly demonstrated television system, and also the world's first fully electronic colour television tube...
, based on the electromechanical Nipkow disk
Nipkow disk
A Nipkow disk , also known as scanning disk, is a mechanical, geometrically operating image scanning device, invented by Paul Gottlieb Nipkow...
and used by the BBC in experimental broadcasts through the 1930s. All-electronic designs based on the cathode ray tube
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
, such as Vladimir Zworykin
Vladimir Zworykin
Vladimir Kozmich Zworykin was a Russian-American inventor, engineer, and pioneer of television technology. Zworykin invented a television transmitting and receiving system employing cathode ray tubes...
's Iconoscope
Iconoscope
The Iconoscope was the name given to an early television camera tube in which a beam of high-velocity electrons scans a mosaic of photoemissive isolated granules...
and Philo T. Farnsworth's Image dissector
Image dissector
An image dissector, also called a dissector tube, is a video camera tube in which photocathode emissions create an "electron image" which is then scanned to produce an electrical signal representing the visual image...
, supplanted the Baird system by the 1940s and remained in wide use until the 1980s, when cameras based on solid-state image sensor
Image sensor
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...
s such as CCDs
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
(and later CMOS
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
active pixel sensor
Active pixel sensor
An active-pixel sensor is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web...
s) eliminated common problems with tube technologies such as image burn-in and made digital video
Digital video
Digital video is a type of digital recording system that works by using a digital rather than an analog video signal.The terms camera, video camera, and camcorder are used interchangeably in this article.- History :...
workflow
Workflow
A workflow consists of a sequence of connected steps. It is a depiction of a sequence of operations, declared as work of a person, a group of persons, an organization of staff, or one or more simple or complex mechanisms. Workflow may be seen as any abstraction of real work...
practical.
Video cameras are used primarily in two modes. The first, characteristic of much early broadcasting, is live television
Live television
Live television refers to a television production broadcast in real-time, as events happen, in the present. From the early days of television until about 1958, live television was used heavily, except for filmed shows such as I Love Lucy and Gunsmoke. Video tape did not exist until 1957...
, where the camera feeds real time
Present
Present is a time that is neither past nor future.Present may also refer to:- Time and timing :* Present tense, the grammatical tense of a verb* Before Present, radiocarbon dates relative to AD 1950* Presenting, a medical term* Presenteeism...
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
Videotape
A videotape is a recording of images and sounds on to magnetic tape as opposed to film stock or random access digital media. Videotapes are also used for storing scientific or medical data, such as the data produced by an electrocardiogram...
was the primary format used for this purpose, but optical disc
Optical disc
In computing and optical disc recording technologies, an optical disc is a flat, usually circular disc which encodes binary data in the form of pits and lands on a special material on one of its flat surfaces...
media, hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
, and flash memory
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
in tapeless camcorder
Tapeless Camcorder
A tapeless camcorder is a camcorder that does not use video tape for the digital recording of video productions as 20th century ones did. Tapeless camcorders record video as digital computer files onto random access data storage devices such as optical discs, hard disk drives and solid-state flash...
s are all increasingly used. Recorded video is used in television and film production, and more often surveillance
Surveillance
Surveillance is the monitoring of the behavior, activities, or other changing information, usually of people. It is sometimes done in a surreptitious manner...
and monitoring tasks where unattended recording of a situation is required for later analysis.
Modern video cameras have numerous designs and uses, not all of which resemble the early television cameras.
- Professional video cameraProfessional video cameraA professional video camera is a high-end device for creating electronic moving images...
s, such as those used in television production and sometimes filmmakingFilmmakingFilmmaking is the process of making a film, from an initial story, idea, or commission, through scriptwriting, casting, shooting, directing, editing, and screening the finished product before an audience that may result in a theatrical release or television program...
in digital cinemaDigital cinemaDigital cinema refers to the use of digital technology to distribute and project motion pictures. A movie can be distributed via hard drives, optical disks or satellite and projected using a digital projector instead of a conventional film projector...
; these may be television studioTelevision studioA television studio is an installation in which a video productions take place, either for the recording of live television to video tape, or for the acquisition of raw footage for post-production. The design of a studio is similar to, and derived from, movie studios, with a few amendments for the...
-based or mobile in the case of an electronic field productionElectronic field productionElectronic field production is a television industry term referring to a video production which takes place in the field, outside of a formal television studio, in a practical location or special venue...
(EFP). Such cameras generally offer extremely fine-grained manual control for the camera operator, often to the exclusion of automated operation. - CamcorderCamcorderA camcorder is an electronic device that combines a video camera and a video recorder into one unit. Equipment manufacturers do not seem to have strict guidelines for the term usage...
s, which combine a camera and a VCR or other recording device in one unit; these are mobile, and are widely used for television production, home movieHome movieHome movie may mean:*Home movies, referring to private or amateur motion picture photographic products shot and printed in any video or film format....
s, electronic news gatheringElectronic news gatheringENG is a broadcasting industry acronym which stands for electronic news gathering. It can mean anything from a lone broadcast journalist reporter taking a single professional video camera out to shoot a story, to an entire television crew taking a production truck or satellite truck on location...
(ENG) (including citizen journalismCitizen journalismCitizen journalism is the concept of members of the public "playing an active role in the process of collecting, reporting, analyzing and disseminating news and information," according to the seminal 2003 report We Media: How Audiences are Shaping the Future of News and Information...
), and similar applications. Some digital ones are- Pocket video cameraPocket video cameraA pocket video camera is a tapeless camcorder that is small enough to be carried in one's pocket. Most pocket video cameras resemble mobile phones in shape and size, unlike traditional cameras....
s.
- Pocket video camera
- Closed-circuit televisionClosed-circuit televisionClosed-circuit television is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors....
(CCTV) generally use pan tilt zoom cameras (PTZ), 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 (e.g. radiationRadiation hardeningRadiation hardening is a method of designing and testing electronic components and systems to make them resistant to damage or malfunctions caused by ionizing radiation , such as would be encountered in outer space, high-altitude flight, around nuclear reactors, particle accelerators, or during...
, high heat, or toxic chemical exposure).- WebcamWebcamA webcam is a video camera that feeds its images in real time to a computer or computer network, often via USB, ethernet, or Wi-Fi.Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a video camera...
s are video cameras which stream a live video feed to a computer. Larger video cameras (especially camcorders and CCTV cameras) can be similarly used, though they may need an analog-to-digital converterAnalog-to-digital converterAn analog-to-digital converter is a device that converts a continuous quantity to a discrete time digital representation. An ADC may also provide an isolated measurement...
in order to store the output on a computer or digital video recorderDigital video recorderA digital video recorder , sometimes referred to by the merchandising term personal video recorder , is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device...
or send it to a wider network.
- Webcam
- Most 21st century video cameras are digital cameraDigital cameraA digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...
s which convert the signal directly to a digital output; such cameras are often small, even smaller than CCTV security cameras, and are often used as webcamWebcamA webcam is a video camera that feeds its images in real time to a computer or computer network, often via USB, ethernet, or Wi-Fi.Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a video camera...
s or optimized for still-camera use. The majority are incorporated directly into computer or communications hardware, particularly mobile phoneMobile phoneA mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
s, though analog videoAnalog videoAnalog video is a video signal transferred by an analog signal. An analog color video signal contains luminance, brightness and chrominance of an analog television image...
equipment remains in use. - Special systems, like those used for scientific research, e.g. on board a satelliteSatelliteIn the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
or a spaceprobe, or in artificial intelligenceArtificial intelligenceArtificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
and roboticsRoboticsRobotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture and application of robots...
research. Such cameras are often tuned for non-visible radiation for Infrared photographyInfrared photographyIn infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about...
(for night visionNight visionNight vision is the ability to see in low light conditions. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range...
and heat sensing) or X-rayX-rayX-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
(for medical and video astronomySpeckle imagingSpeckle imaging describes a range of high-resolution astronomical imaging techniques based either on the shift-and-add method or on speckle interferometry methods...
use).
See also
- FireWire cameraFireWire cameraFireWire cameras use the IEEE 1394 bus standard for the transmission of audio, video and control data. FireWire is Apple Computer's trademark for the IEEE 1394 standard....
- Professional video cameraProfessional video cameraA professional video camera is a high-end device for creating electronic moving images...
- Radar imaging
- Television production
- Three-CCD
- Video camera tubeVideo camera tubeIn older video cameras, before the mid to late 1980s, a video camera tube or pickup tube was used instead of a charge-coupled device for converting an optical image into an electrical signal. Several types were in use from the 1930s to the 1980s...
- VideotelephonyVideotelephonyVideotelephony comprises the technologies for the reception and transmission of audio-video signals by users at different locations, for communication between people in real-time....