Canon PowerShot A580 2463B020 User Guide (en)

Adjust the exposure compensation to a positive value to avoid making 
the subject too dark when it is backlit or shot against a bright 
background. Adjust the exposure compensation to a negative value to 
avoid making the subject too bright in night shots or when shot against 
a dark background.
To Cancel the Exposure Compensation:
Restore the compensation value to [0].
Adjusting the Exposure Compensation 
(Still Images)
Available Shooting Modes
p. 190
Adjust the exposure 
1. Press the 
2. Use the 
 button to select 
and the 
 button to adjust the 
exposure compensation.
3. Press the 
Exposure shift is used to change the exposure when shooting 
movies (p. 88).