Mass Communication

Topics: Photographic lens, Focal length, Film crew Pages: 57 (20333 words) Published: June 18, 2013
1.1 Working principle of video camera
The television camera changes light into an electronic signal that can be stored (using video tape, optical disks, or computer memory, transmitted, and displayed on a television receiver or monitor. Whether digital or analog, and regardless of their size, cost, and quality, all video cameras operate on the same basic principle: they transduce (translate) the optical image that the lens sees into a corresponding video picture. More specifically, the camera converts an optical image into electrical signals that are reconverted by a television receiver into visible screen images. To fulfill this function, each video camera needs three basic elements: the lens, the imaging device, and the viewfinder.

The video camera translates the optical light image as seen by the lens into a corresponding picture on the screen. The light reflected off an object is gathered and transmitted by the lens to the beam splitter, which splits the white light into red, green, and blue (RGB) light beams. These beams are then transformed by the imaging device into electric energy, which is amplified and processed into a video signal. It is then reconverted into video pictures by the viewfinder.

We normally classify video cameras by how they are used: shoulder-mounted (large) and handheld (small) camcorders, ENG/EFP (electronic news gathering/electronic field production) cameras, studio cameras, and digital cinema cameras.

Studio camera
Most television studio cameras stand on the floor, usually with pneumatic or hydraulic mechanisms called pedestals to adjust the height, and are usually on wheels. Any video camera when used along with other video cameras in a multiple-camera setup is controlled by a device known as CCU (camera control unit), to which they are connected via a Triax, Fibre Optic or the almost obsolete multicore cable. The CCU along with genlock and other equipment is installed in the production control room (PCR) often known as the Gallery of the television studio. When used outside a formal television studio in outside broadcasting (OB), they are often on tripods that may or may not have wheels (depending on the model of the tripod). Initial models used analog technology, but are now obsolete, supplanted by digital models. Studio cameras are light and small enough to be taken off the pedestal and the lens changed to a smaller size to be used on a Multiple-camera setup's shoulder, but they still have no recorder of their own and are cable-bound. Cameras can be mounted on a tripod, a dolly or a crane, thus making the cameras much more versatile than previous generations of studio cameras. These cameras have a tally light, a small signal-lamp used that indicates, for the benefit of those being filmed as well as the camera operator, that the camera is 'live' - i.e. its signal is being used for the 'main program' at that moment. ENG Cameras

Though by definition, ENG (Electronic News Gathering) video cameras were originally designed for use by news camera operators, these have become the dominant style of professional video camera for most video productions, from dramas to documentaries, from music videos to corporate video training. While they have some similarities to the smaller consumer camcorder, they differ in several regards: * ENG cameras are larger and heavier (helps dampen small movements), and usually supported by a camera shoulder support or shoulder stock on the camera operator's shoulder, taking the weight off the hand, which is freed to operate the zoom lens control. * The camera mounts on tripods with Fluid heads and other supports with a quick release plate. * 3 CCDs or CMOS active pixel sensors are used, one for each of the primary colors * They have interchangeable lenses.

* The lens is focused manually and directly, without intermediate servo controls. However the lens zoom and focus can be operated with remote controls with a television...
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