“ I have taken notice that in digital cameras, extraordinary detectors help to {focus|concentrate|maintain focus|target|a**** automatically. These sensors connected with some surveillance cameras change in contrast, while others employ a beam involving infra-red (IR) light, particularly in low lighting. Higher specification cameras from time to time use a mix of both models and likely have Face Priority AF where the digital camera can 'See' a face while keeping focused only in that. Thank you for sharing your opinions on this site. ”