Canon PowerShot SX400 IS Black Manual (en)

The area in focus is not magnified in the following cases when the 
shutter button is pressed halfway.
If a face was not detected, if the person is too close to the 
camera and their face is too large for the screen, or if the 
camera detects subject movement
When digital zoom is used (
When Tracking AF is used (
When a TV is used as a display (
Checking for Closed Eyes
 Still Images 
] is displayed when the camera detects that people may have 
closed their eyes.
Configure the setting.
Press the [
] button, 
choose [Blink Detection] on the 
] tab, and then choose [On]