Science Fair Project Encyclopedia
Professional video camera
A professional video camera (often called a "television camera" even though the use has spread) is a high-end device for recording electronic moving images (as opposed to a movie camera, that records the images on film). Originally developed for use in television studios, they are now commonly used for corporate and educational videos, music videos, direct-to-video movies, etc. Less advanced video cameras used by consumers are often referred to as camcorders.
There are two types of professional video cameras: High end portable, recording cameras (which are, confusingly, called camcorders too) used for ENG image acquisition, and studio cameras which lack the recording capability of a camcorder, and are often fixed on studio pedestals.
Professional video cameras capture and transfer two dimensional images sequentially, at specified capture rates, usually in the visible range of the electromagnetic spectrum. These images can then be transmitted to television receivers and replayed on a screen (CRT or LCD) at a frame rate approximating that used by the camera. They serve as a means of communicating valuable information across large distances: world events, telerobotic exploration of planets or satellites, space stations, etc.
It is common for professional cameras to split the incoming light into the three primary colors that humans are able to see, feeding each color into a separate pickup tube (in older cameras) or charge-coupled device (CCD). Some high-end consumer cameras also do this, producing a higher-quality image than what is normally possible with just a single video pickup.
Most studio cameras stand on the floor, usually with pneumatic or hydraulic mechanisms to adjust the height, and are usually on wheels. Any video camera when used along with other video cameras in a studio setup is controlled by a device known as CCU (camera control unit), to which they are connected via a Triax or Multicore cable. The camera control unit along with other equipments is installed in the production control room often known as Gallery of the television studio. When used outside a studio, they are often on tracks. Initial models used analog technology, but digital models are becoming more common. Some studio cameras are light and small enough to be taken off the pedestal and used on a cameraman's shoulder, but they still have no recorder of their own and are cable-bound.
ENG video cameras are similar to consumer camcorders, and indeed the dividing line between them is somewhat blurry, but a few differences are generally notable:
- They are bigger, and usually have a shoulder stock for stabilizing on the cameraman's shoulder
- They use 3 CCDs
- They have removable/swappable lenses
- All settings like white balance, focus and iris can be manually adjusted, and automatics can be completely disabled
- If possible, these functions will be even adjustable machanically (especially focus and iris), not by passing signals to an actuator or digitally dampening the video signal.
- They will have professional connectors - BNC for video and XLR for audio
- A complete timecode section will be available, and multiple cameras can be timecode-synchronized with a cable
- Finally, they will use a professional medium like some variant of Betacam or DVCPRO, though some professional DV cameras are available, Canon's XL1/XL2 and Sony's VX2100 cameras being examples.
Some manufacturers build camera heads, which only contain the optical array, the CCD sensors and the video coder, and can be used with a studio adaptor for connection to a CCU or various dock recorders for direct recording in the preferred format, making them very versatile. However, this versatility leads to greater size and weight, and dock cameras have become rare in recent years.
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