“ I have noticed that in digital cameras, unique receptors help to {focus|concentrate|maintain focus|target|a**** automatically. Those sensors of some cameras change in in the area of contrast, while others use a beam with infra-red (IR) light, especially in low lighting. Higher standards cameras from time to time use a combination of both methods and probably have Face Priority AF where the digital camera can 'See' the face while focusing only in that. Thank you for sharing your thinking on this web site. ”