Canon PowerShot SD4500 IS Digital ELPH User Manual page 86

The focus can be locked. After locking the focus, the focal distance will not
change even when you release your finger from the shutter button.
Lock the focus.
Keep the shutter button pressed halfway
and press the 4 button.
The focus locks and
AFL
a ppears on the
screen=
if you release your finger from the shutter
button and press the 4 button again,
AFL
wil! disappear and the focus will unlock.
Composethesceneandshoot.
WhiBe the shutter button is pressed halfway, the focus and exposure will
continue to adjust, allowing you to take pictures of moving subjects without
missing a shoL
Choose [Servo AF].
Press the MENU button to choose [Servo
AF] in the O tab, then press the 4_
buttons to choose [On].
Focus.
The focus and exposure will be maintained
where the blue AF frame appears while
you press the shutter button halfway.
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