The Video Camera

The lens is a very valuable component of the video camera system. The lens system also have several parts. These parts are the zoom lens and the lens mount. The zoom lens covers a wide range of focal lengths from the wide angle to telephoto. The range can be from 400mm to 1,000mm. In addition, there are two possibilites for operating the zoom. The first possibility is by manually adjusting the length of the zoom lens with a setting ring or by the motor-driven zoom where the focal length is continuously varied in the direction of the telephotolens or the wide-angle lens at the press of a button. The wide-angle lens gives a different effect to the angle of view. The wide-angle range attains a larger angle.

The lens mounted system allows the user to exchange lens for another to render a better camera shot. The lens mounted system allows the user to work at an extremely wide angle or a high power telephoto lens.

In the video camera, a vacuum replaces the film. The image captured by the camera is transmitted electronically onto magnetic tape (video tape) depending upon the tube system within each camera. In the first cameras, the vidicon tube coverted the optical image to electrical signal. The tube system, like a photo camera, breaks down the image into three colors:blue, green, and red. The camera then breaks down the primary color signals into video signals. The video recorder captures the video signals and converts them back into images. In addition, cameras can have single, two or three tube. The signal-tube camera was developed to be light, convenient, compact and resonably priced. The primary color signals in a single-tubed camera are received by a single vidicon, in which a stripe filter is installed in front of the recording surface. This stripe filter consists of a large number of individual filters which are aligned alternately over a width of several dozen micros. The optical image of the subject is broken down by the filter into striped primary color images and shown in this way on the recording surface. The two-tubed color video camera has two vidicons, where one vidicon receives the color image, and the other captures the black and white image. By combining black and white with color images, the camera gives very clear color pictures. The three-tube color video camera breaks down the light passing through the lens by an optical seperation system into the three primary colors, which are fed seperately by a lens system to three vidicons. The vidicons filter the colors so that only blue, green, and red light pass through it.

Sources:
--Lanzendorf, Peter.The Video Taping Handbook.Harmony Books.1983
--Sony

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