In consumer units these adjustments are often automatically controlled by the camcorder, but can be adjusted manually if desired. Professional-grade units offer user control of all major optical functions.
The imager, often a CCD, or a photodiode array which may be an Active Pixel Sensor, converts light into an electrical signal. The camera lens projects an image onto the imager surface, exposing the photosensitive array to light. This light exposure is converted into an electrical charge. At the end of the timed exposure, the imager converts the accumulated charge into a continuous analog voltage at the imager’s output terminals. After the conversion is complete, the photosites reset to start the exposure of the next video frame. In many cases the photosites (per pixel) are actually reset globally by charging to a fixed voltage, and discharged towards zero individually proportionally to the accumulated light, because it is simpler to manufacture the sensor that way.
Most camcorders use a single imaging sensor with integrated colour filters, per pixel, to enable red, green and blue to be sensed, each on their own set of pixels. The individual pixel filters present a significant manufacturing challenge. However some camcorders, even consumer grade devices such as the JVC GZ-HD3, introduced around 2007, are triple sensor cameras, usually CCD but could be CMOS. In this case the exact alignment of the three sensors so that the red, green and blue components of the video output are correctly aligned, is the manufacturing challenge.
The recorder writes the video signal onto a recording medium, such as magnetic videotape. Since the record function involves many signal-processing steps, some distortion and noise historically appeared on the stored video; playback of the stored signal did not have the exact characteristics and detail as a live video feed. All camcorders have a recorder-controlling section, allowing the user to switch the recorder into playback mode for reviewing recorded footage, and an image-control section controlling exposure, focus and color balance.
The image recorded need not be limited to what appeared in the viewfinder. For documenting events (as in law enforcement), the field of view overlays the time and date of the recording along the top and bottom of the image. The police car or constable badge number to which the recorder was given, the car’s speed at the time of recording, compass direction and geographical coordinates may also be seen.