Digital Video Cameras

A digital video camera, or camcorder, is an electronic device that can record moving images. Since many mobile phones and still cameras can often record video as well the term “video camera” is usually reserved for devices that have video capture and recording as their primary function. The earliest video cameras were tape-based devices which recorded analogue video signals onto videotape cassettes. All modern video cameras are digital and tape has gradually been replaced by hard disk and SD card storage.

Digital video cameras contain three major components: lens, imager and recorder.The lens gathers and focuses light on the imager. The imager (an electronic sensor) converts this light into an electrical signal and the recorder converts the electric signal into video and encodes it in recordable form. Most video cameras have a playback mode that allows the user to view the recorded images.

The lens can be adjusted for aperture, zoom and shutter speed. In consumer video cameras these adjustments are often carried out automatically, with the option of manual override, but in professional units all adjustments are manually controlled.

The imager converts light into an electric signal. The lens projects an image onto the imager surface, where it is converted into an electrical charge which produces a voltage at the output terminals.

The recorder writes the video signal onto a recording medium such as hard disk or SD card. This process can introduce some distortion into the signal.

A Webcam is a type of digital video camera that captures images and transmits them across the Internet, either continuously or at fixed intervals. Webcams can be wireless or connected to a computer. They are widely used for videoconferencing.

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