Canon POWERSHOT A650 IS User Manual page 52

Various Shooting Methods 1117
_ Adjusting Flash Compensation Settings []
See Functions Available in Each Shooting Mode (p. 214).
Flash exposure compensation can be adjusted in the range of -2 to +2
stops in 1/3-stop increments. You can combine the flash exposure
compensation with the camera's exposure compensation function for
balanced exposure of the background when shooting with a flash, tn
"Iv and AV shooting modes, please set [Flash Adjust] to [Auto].
1. Press the @ button.
2. Use the ÷ or _, button to select []
and the ÷ or ._ button to change
the option.
3. Press the @ button.