Nikon D3300 - Manual (Page 124)

104 P, S, A, and M Modes
Mode S (Shutter-Priority Auto)
This mode lets you control shutter speed: choose fast shutter
speeds to “freeze” motion, slow shutter speeds to suggest
motion by blurring moving objects. The camera automatically
adjusts aperture for optimal exposure.
To choose a shutter speed:
1
Rotate the mode dial to S.
Fast shutter speeds (e.g., 1 /
1600
s)
freeze motion.
Slow shutter speeds (e.g., 1 s) blur
motion.
Mode dial