Canon Digital IXUS 500 Quick Start Manual page 84

The FE lock may be released by pressing the zoom lever, MENU
button or
~
button, or by changing the white balance, ISO speed,
photo effect or the shooting mode, or by turning the LCD monitor off.
Although the autofocus function is preset to the AiAF setting (9 AF frames),
you can set it to the center AF frame.
When [AiAF] is set to [On], the AF frame does not appear. When [AiAF] is
set to [Off], however, the AF frame will appear.
No frame On The camera detects the subject and highlights the AF frames,
from 9 available points, that it will use to determine the focus.
o
Off The camera focuses using the center AF frame. This is convenient
for focusing on aspecific part of asubject with greater certainty.
The
0
symbol represents the
AF
frames as they appear in the
LCD
monitor.
MENU
g
In the
L!1
(Rec.) menu, select
See Selecting Menus and Settings (p. 43).
Use the or button to select
[On] or [Off].
You can shoot right after selecting an
option.
Press the MENU button.
The display will return to the Shooting
screen.
76
The focus is locked to the center AF frame when the digital zoom is
used.