Electronics glossary

What is Auto Focus?

Auto Focus — Selects the best focus positions depending on the subject distance. This system uses an infra-red transmitter and an infra-red receiver linked via an electronic logic circuit to a motor which moves the lens back and forth in minute steps. When the shutter button is pressed an infra-red pulse is sent from the camera. The receiving cell measures the strength of the returned pulse and the logic…

Selects the best focus positions depending on the subject distance. This system uses an infra-red transmitter and an infra-red receiver linked via an electronic logic circuit to a motor which moves the lens back and forth in minute steps. When the shutter button is pressed an infra-red pulse is sent from the camera. The receiving cell measures the strength of the returned pulse and the logic circuit translates this strength into a "camera to subject" distance. This information is then used to activate the electric motor that positions the lens to produce the sharpest image.

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