Sony ILCE-6500 Manual page 297

Adjusts the amount of flash light in a range of –3.0 EV to +3.0 EV. Flash compensation changes
the amount of flash light only. Exposure compensation changes the amount of flash light along
with the change of the shutter speed and aperture.
MENU →
1
Selecting higher values (+ side) makes the flash level higher, and lower values (- side)
makes the flash level lower.
Note
[Flash Comp.] does not work when the shooting mode is set to the following modes:
[Intelligent Auto]
[Superior Auto]
[Sweep Panorama]
[Scene Selection]
The higher flash effect (+ side) may not be visible due to the limited amount of flash light available, if
the subject is outside the maximum range of the flash. If the subject is very close, the lower flash
effect (- side) may not be visible.
[316] List of MENU items
Exp.comp.set
Sets whether to apply the exposure compensation value to control both flash light and ambient
light, or just ambient light.
MENU →
1
Menu item details
Ambient&flash:
Applies the exposure compensation value to control both flash light and ambient light.
Ambient only:
Applies the exposure compensation value to control ambient light only.
(Camera Settings1) → [Flash Comp.] → desired setting.
Camera Settings1
(Camera Settings1) → [Exp.comp.set] → desired setting.