JVC GZ-GX3 Detailed User Manual page 11

Advanced Operation with Backlight Compensation
When the subject's face is in backlight or when the expression cannot be
seen clearly, the Intelligent Auto function of this unit automatically increases
its brightness for recording.
If Intelligent Auto fails to function as expected or if the brightness correction
is insufficient, you can increase the brightness by using backlight
compensation in the Manual mode.
"Setting Details" (A p. 91)
<Without backlight compensation>
o
.
<With backlight compensation>
o
.
Useful Shooting Techniques
11