Digital Camera Autofocus
Digital cameras use autofocus to remove the human error out of taking a picture. Most cameras have an autofocus target in the centre of the viewfinder that is best placed over the main subject and this works faultlessly – providing the subject is centrally placed. Autofocus is activated by half-depressing the shutter button and placing your subject in the centre of the frame, until a green confirmation light appears in the viewfinder display.
Autofocus is unable to focus on low contrast subjects like large areas of flat colour, and will track the lens back and forth in error. Solve this problem by recomposing and focussing on an edge of the subject, then pressing the autofocus lock on your camera. The lock holds the focus setting in place, so you can recompose and shoot more creative results.
Another common autofocus problem occurs when a subject falls outside the central portion of the frame and the camera sets focus on another object in the distance by mistake.
