Nikon D3300 User Manual page 260

A
Shutter Speed and Aperture
Shutter speed and aperture are shown in the viewfinder and
information display.
Fast shutter speeds (
example) freeze motion.
Large apertures (such as f/5.6;
remember, the lower the f-number,
the larger the aperture) blur details
in front of and behind the main
subject.
Shutter speed
Aperture
1 /
s in this
1600
Slow shutter speeds (here 1 s) blur
motion.
Small apertures (f/22 in this case)
bring both background and
foreground into focus.
P, S, A, and M Modes 101