Canon POWERSHOT SX40HS User Manual page 91

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 [_ and the MF
indicator appear on the screen.
After you release your finger from the
shutter button, press the 4 button again,
then press the ,_ buttons or turn the _*i_i
dial to choose _. The focus will unlock.
Composethesceneand shoot.
While 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 shot.
Choose [Servo AF].
Press the
MENU
button to choose [Servo
AF] in the 0 tab, then press the ,_
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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