I have noticed that in old digital cameras, specialized sensors help to {focus|concentrate|maintain focus|target|a**** automatically. The particular sensors connected with some surveillance cameras change in in the area of contrast, while others use a beam of infra-red (IR) light, particularly in low light. Higher specification cameras oftentimes use a blend of both models and might have Face Priority AF where the digital camera can ‘See’ the face while keeping focused only upon that. Thanks for sharing your ideas on this web site.