Olympus AZ-4 Zoom - Manual (Page 44)

Autofocus (AF)
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The Autofocus (AF) mechanism automatically adjusts focus. With it, the camera measures
the distance to a subject and adjusts the lens so that the subject is in focus. Currently, with
the exception of a few cameras for professional use, this function is included in most of the
single lens reflex and compact cameras that are now on the market. Of course, this function
is used in the AZ-4 Zoom. In the AZ-4 Zoom, focusing is done by a newly-developed
"Phase-Difference" detection system. In this system, light from the subject is picked up by a
special sensor and any inconsistencies (phase differences) in the image are used by a
microprocessor chip to calculate the best focus setting. Since the lens used in the AZ-4
Zoom is very accurate, correct focusing is even more accurate and accomplished by just
aiming the lens at the subject. When there is no light reflected from the subject, for example
in a dark room, focusing is performed using a beam of light from the camera (the AF-
Illuminator).
Autofocus is designed so that the subject in the center of the picture frame is correctly
focused. However, sometimes you may want a subject that is not in the center of the frame
to be in focus; for such cases, the AZ-4 Zoom is also equipped with a focus lock
(1) Subject that does not
include vertical lines
(2) Subject with low
contrast
(3) A rapidly moving
subject