Sony Cyber-shot DSC-P7 Operating Instructions Manual page 54

Even if it is difficult to focus in Center AF
shooting because the subject is not in the
center of the frame. you can
focus
in this
situation using the AF lock. For example,
when you are shooting two human subjects,
and there is a gap he!ween them, the
camera
may focus on the background visible in the
gap. In a case iike this, use AIi Iock to
ensure the subjects
are
in carrect focus.
First, the focus for the subject you are
aiming at will be adjusted. When the
AE/.AF lock indicator stops flashing
and remains on. and there is a beeping
sound, focus adjustment is completed.
The shutter clicks, the image will be
recorded with the proper focus for the
human sub.jccts.