ocr: PICTURES THAT WILL FOOL THE AUTOFOCUS.. Most compacts use a simple autofocus system that will focus on whatever is in the target area in the centre of the viewf - inder. Both of these Pictures would result in a sharp background and blurred subject. Almost all cameras have a focus lock facility. This is usually achieved by taking up the first pressure on the shutter button with the DESIRED subject in the target area - then, whilst maintaining the pressure on the shutter button, which holds the rocus, the picture is recomposed in the viewfinder, and the button pressed fully. The result is a shar ...