Nikon D3300 - Manual (Page 139)

119 P, S, A, and M Modes
To choose a value for exposure compensation, keep the E (N)
button pressed and rotate the command dial until the desired
value is selected in the viewfinder or information display. Normal
exposure can be restored by setting exposure compensation to
±0 (adjustments to exposure compensation in
% and I modes
will be reset when another mode is selected). Exposure
compensation is not reset when the camera is turned off.
+
E (N) button Command dial Information display
–0.3 EV +2 EV
A The Information Display
Exposure compensation options can also be
accessed from the information display (
0 9).
A Mode M
In mode M, exposure compensation affects only the exposure
indicator.
A
Using a Flash
When a flash is used, exposure compensation affects both background
exposure and flash level.