Nikon D3300 - Manual (Page 101)

81 More on Photography
Focus Lock
Focus lock can be used to change the composition after focusing
in AF-A, AF-S, and AF-C focus modes (
0 74), making it possible to
focus on a subject that will not be in a focus point in the final
composition. If the camera is unable to focus using autofocus
(
0 76), focus lock can also be used to recompose the
photograph after focusing on another object at the same
distance as your original subject. Focus lock is most effective
when an option other than
e (Auto-area AF) is selected for AF-
area mode ( 0 78).
1
Focus.
Position the subject in the
selected focus point and
press the shutter-release
button halfway to initiate
focus. Check that the in-
focus indicator (
I) appears
in the viewfinder.
2
Lock focus.
AF-A and AF-C focus modes
: With the
shutter-release button pressed
halfway (q), press the
A (L) button
(w) to lock focus. Focus will remain
locked while the
A (L) button is
pressed, even if you later remove your
finger from the shutter-release
button.
Shutter-release button
A (L) button