“ I have noticed that in video cameras, special receptors help to {focus|concentrate|maintain focus|target|a**** automatically. Those kind of sensors associated with some cameras change in in the area of contrast, while others make use of a beam with infra-red (IR) light, particularly in low lighting. Higher specification cameras often use a mix of both devices and might have Face Priority AF where the camera can 'See' the face and concentrate only in that. Many thanks for sharing your thinking on this site. ”