Canon PowerShot SX150 IS User Manual page 72

Detecting a Face and Shooting (Smart Shutter)
Changing the number of shots
After choosing
Even if your face is not detected after joining the subjects, the shutter will
release approximately 15 seconds later.
72
Join the subjects and look at the
camera.
When the camera detects a new face, the
lamp and self-timer sound will speed up
(the lamp remains lit when the flash will
fire), and 2 seconds later the shutter will
release.
To cancel shooting with the timer after
countdown has started, press the n
button.
in Step 1, press the op buttons.