Choose the slowest shutter speed available with a flash in modes P and A.

Regardless of the setting chosen for e2 [Flash shutter speed], shutter speeds can be as slow as 30 s in modes S and M or at flash settings of slow sync, slow rear-curtain sync, or red-eye reduction with slow sync.

A Custom Settings: Fine-Tuning Camera Settings

a: Autofocus

b: Metering/Exposure

c: Timers/AE Lock

d: Shootin/Display

e: Bracketing/Flash

f: Controls

g: Movie