|
Whether we are shooting with the finest broadcast-quality studio camera or working with a small portable video camera, the main parts of the camera and the principles on which they are based are virtually the same.
When the camera is pointed at a subject, the lens gathers the light reflected from that scene and focuses it on the beam splitter. The beam splitter consists of various prisms or filters that splits the white light of the image into the three video primaries-red, green, and blue light beams, usually referred to as RG B.
Once the white light has been divided into the three primary colours, the light beams are directed towards the principal electronic component that converts light into electricity-either a solid-state element known as a charge coupled device (CCD) or a camera pick-up tube. The CCD and the camera pick-up tube perform the same basic function-transforming the incoming light into electrical signals that can be recorded on videotape and/or be seen in the camera's viewfinder. The CCD sensor (Fig. 2.2) is a small stamp-sized solidstate device normally called the CCD or the chip. It contains hundreds of thousands of image-sensing elements called pixels that are arranged in horizontal and vertical rows. Pixels are light sensitive and the more the number of pixels in the imaging chip, the higher the resolution of the video image.
After the pixel information in the CCD is converted into electric charge, all the electric charges combine to become the video signals for the three primary light colours. These RG B signals make up the chrominance (colour) information. The black-and-white signal or luminance information is generated internally.
Once the red, green, and blue light have been transformed into electrical RG B signals, an electronically mixed combination and permutation of these three colours gives us the various colours we ,see on our television screen. These signals are amplified and processed and then reconverted into video pictures by the viewfinder (Fig. 2.3).
|
Participants