A camcorder is a portable consumer electronics device for recording video and audio using a built-in recorder unit. The camcorder contains both a video camera and a video recorder in one unit, hence its compound name. This compares to previous technology where an acquisition and recording devices would be separate.
The earliest camcorders, developed by companies such as JVC, Sony, and Kodak, used analog videotape. Since the 1990s recording onto digital tape has become the norm. Starting from early 2000s tape as storage media is being gradually replaced with tape-free solutions like optical disks, hard disk drives and solid-state memory.
All tape-based camcorders have removable media in form of video cassettes. Solid-state camcorders can have either removable media in form of memory cards, or built-in memory, or both. HDD-based camcorders usually have non-removable media in form of a hard disk drive.
Camcorders that do not use magnetic tape are often called tapeless camcorders. Camcorders that use two different types of media, like built-in HDD and memory card, are often called hybrid camcorders.
History
Before the camcorder. This separate portable Betamax recorder and camera arrangement slightly predates the first camcorders
Video cameras were originally designed for broadcasting television images — see television camera. Cameras found in television broadcast centres were extremely large, mounted on special trolleys, and wired to remote recorders located in separate rooms. As technology advanced, miniaturization eventually enabled the construction of portable video-cameras and portable video-recorders.
Prior to the introduction of the camcorder, portable video-recording required two separate devices: a video-camera and a VCR. Specialized models were introduced by both JVC (VHS) and Sony (Umatic & Betamax) to be used for mobile work. The portable VCR consisted of the cassette player/recorder unit, and a television tuner unit. The cassette unit could be detached and carried with the user for video recording. While the camera itself could be quite compact, the fact that a separate VCR had to be carried generally made on-location shooting a two-man job, however the advent of these portable VCRs helped to eliminate the phrase "film at eleven". Rather than wait for the lengthy process of film developing, portable VCRs and video cameras allowed video to be shown during the 6 o'clock news.
In 1982, two events happened that eventually led to the home camcorder boom: JVC introduced the VHS-C format, and Sony released the first professional camcorder named Betacam. VHS-C was essentially VHS with a reduced-size cassette that had been designed for portable VCRs. Sony's Betacam was a standard developed for professional camcorders, which used component video to provide a superior picture. At first, cameramen did not welcome Betacam, because before it, carrying and operating the VCR unit was the work of a video engineer; after Betacam they came to be required to operate both video camera and VCR. However the cable between cameramen and video engineers was eliminated, the freedom of cameramen improved dramatically and Betacam quickly became the standard for both news-gathering and in-studio video editing.
In 1983, Sony released the Betamax-based Betamovie, the first consumer camcorder. A novel technique was used to reduce the size of the spinning video head drum, which was then used for many subsequent camcorders. The unit was bulky by today's standards, and since it could not be held in one hand, was typically used resting on a shoulder. Some later camcorders were even larger, because the Betamovie models had only optical viewfinders and no playback or rewind capability. Most camcorders were and still are designed for right-handed operation, though a few possessed ambidextrous ergonomics.
Within a short time JVC released its own camcorder using its pre-existing VHS-C format. The VHS-C cassette held enough tape to record 40 or 120 minutes of VHS video, while a mechanical adapter enabled playback of VHS-C videocassettes in home VCRs. This first model can be seen in the movie Back to the Future.[1] After seeing the popularity of the small VHS-C "palmcorders", Sony redesigned its Betamax system to create the Video8 standard. Video8 eliminated the problem of short running time, by using an all-new metal composition video cassette. 8 mm video used a tape whose width is 33% less than VHS/Betamax tape (~12.7 mm), allowing even further miniaturization in the recorder's tape-transport assembly and cassette media.
Both VHS-C and 8 mm video represented a trade-off for the consumer. Although the Video8 and Hi8 camcorders produced quality equal to VHS-C and Super VHS-C camcorders (250/420 lines horizontal), the standard 8 mm cassette had the advantage with up to two hours length (four hours in slow mode). On the down side, since the 8 mm format was incompatible with VHS, 8 mm recordings could not be played in consumers' VHS VCRs. Equally important entry-level VHS-C camcorders were priced less than 8 mm units, and thus neither "won" the war. It became a stalemate. (Side note - In 1986 companies like Panasonic began releasing full-sized VHS/S-VHS camcorders, which offered up to 3 or 9 hours record time, and thus found a niche with videophiles, industrial videographers, and college TV studios.)
In the mid-1990s, the camcorder reached the digital era with the introduction of DV and miniDV. Its cassette media was even smaller than 8 mm media, allowing another size reduction of the tape transport assembly. The digital nature of miniDV also improved audio and video quality over the best of the analog consumer camcorders (SVHS-C, Hi8), although some users still prefer the analog nature of Hi8 and Super VHS-C, since neither of these produce the "background blur" or "mosquito noise" of Digital compression. Variations on the DV camcorder include the Digital8 camcorder and the MPEG2-based DVD camcorder.
The evolution of the camcorder has seen the growth of the camcorder market as price reductions and size reductions make the technology more accessible to a wider audience. When camcorders were first introduced, they were bulky shoulder-operated luggables that cost over $1,500 US dollars[citation needed]. As of 2008, an entry-level camcorders fit in the palm of a person's hand and is sold at a retail price of approximately $100 US dollars (http://cameras.pricegrabber.com/camcorders/m/17729872).
Overview
Major components
Camcorders contain 3 major components: lens, imager, and recorder. The lens gathers and focuses light on the imager. The imager (usually a CCD or CMOS sensor on modern camcorders; earlier examples often used vidicon tubes) converts incident light into an electrical (video) signal. Finally, the recorder encodes the video signal into a storable form. More commonly, the optics and imager are referred to as the camera section.
The lens is the first component in the camera-section's "light-path". The camcorder's optics generally have one or more of the following adjustments: aperture (to control the amount of light), zoom (to control the field-of-view), and shutter speed (to capture continuous motion.) In consumer units, these adjustments are automatically controlled by the camcorder's electronics, generally to maintain constant exposure onto the imager. Professional units offer direct user control of all major optical functions (aperture, shutter-speed, focus, etc.)
The imager section is the eye of the camcorder, housing a photosensitive device(s). The imager converts light into an electronic video-signal through an elaborate electronic process. The camera lens projects an image onto the imager surface, exposing the photosensitive array to light. The light exposure is converted into electrical charge. At the end of the timed exposure, the imager converts the accumulated charge into a continuous analog voltage at the imager's output terminals. After scan-out is complete, the photosites are reset to start the exposure-process for the next video frame. In modern (digital) camcorders, an analog-to-digital (ADC) converter digitizes the imager (analog) waveform output into a discrete digital-video signal.
The third section, the recorder, is responsible for writing the video-signal onto a recording medium (such as magnetic videotape.) The record function involves many signal-processing steps, and historically, the recording-process introduced some distortion and noise into the stored video, such that playback of the stored-signal may not retain the same characteristics/detail as the live video feed.
All but the most primitive camcorders imaginable also need to have a recorder-controlling section which allows the user to control the camcorder, switch the recorder into playback mode for reviewing the recorded footage and an image control section which controls exposure, focus and white-balance.
The image recorded need not be limited to what appeared in the viewfinder. For documentation of events, such as used by police, the field of view overlays such things as the time and date of the recording along the top and bottom of the image. Such things as the police car or constable to which the recorder has been allotted may also appear; also the speed of the car at the time of recording. Compass direction at time of recording and geographical coordinates may also be possible. These are not kept to world-standard fields; "month/day/year" may be seen, as well as "day/month/year", besides the ISO standard "year-month-day". And the Danish police have the speed of the police car in the units "Km/t" sic (time being Danish for "hour").
Posts
