Canon 115 HS, 117 HS Tracking AF, Center

Changing the AF Frame Mode
96
Tracking AF
You can choose the subject you want to focus on and shoot (p. 97).
Center
The AF frame is locked to the center. This is effective for focusing on a
specific point.
Changing the Composition with the Focus Lock
While you keep the shutter button pressed halfway, the focus and exposure
are locked. You can now recompose and shoot. This is called Focus Lock.
Focus.
Center the subject you want in focus, and
press the shutter button halfway.
Confirm that the AF frame on the subject is
green.
Recompose.
Keep the shutter button pressed halfway
and move the camera to recompose the
scene.
Shoot.
Press the shutter button fully.
You can reduce the AF frame size
•Press the n button to choose [AF Frame Size] from the 4 tab, then
choose [Small].
•The AF frame is set to [Normal] when using the digital zoom (p.55) or digital
tele-converter (p.56).
If the camera cannot focus when you press the shutter button halfway, the
AF frame will turn yellow and will appear.