Tuesday, May 20, 2008

Major Components

All video cameras contain 3 major components - the lens, imager, and recorder. The lens gathers and focuses the light on the imager, which is normally a charge coupled device (CCD) or CMOS sensor IC. Finally, the recorder will encode the video signal into a form that can be stored. Commonly, the optics and imager are known as the camera section.

The optic lens is the first component in the camera section's light path. The optics normally have one or more the following adjustments:

1. aperture - controls the amount of light
2. zoom - controls the field of view
3. shutter speed - captures continuous motion

In most consumer units, these adjustments are automatically controlled by the video camera's electronics, normally to maintain constant exposure onto the imager.

The imager is the "eye" of the camera, housing a photo sensitive device or devices. The imager works to convert light into an electronic video signal through an elaborate electronic process. The camera lens projects an image to the imager surface, exposing the photo sensitive array to the light.

The light exposure is then converted into an electrical charge. Towards the end of the timed exposure, the imager will convert the accumulated charge into a continuous analog voltage at the imager's output terminals.

The third piece, the recorder, is responsible for writing the video signal to a recording medium, such as magnetic videotape. The recording function involves many steps of signal processing, and historically, the recording process introduced some distortion and noise to the stored video, such that the playback of stored signal may not retain the same detail as the original live feed.

All but the most primitive of video cameras will also need to have a recorder controlling section which will allow you to control the camera. You can also swich the recorder into playback mode for reviewing your recorded footage.

The image you recorded doesn't need to be limited to what appeared in the view finder. For a documentation of events such as those used by the police, the fields of view will overlay such things as the time and date of the recording along the top and bottom of the image.

As you can probably tell now, a high definition video camera is very complex indeed. There are several other parts involved as well, although the above are the most important. A HD video camera is very complex in build, making it something that is more than worth the time it takes to create.

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