Nikon D90 - Manual (Page 77)

57
h
Focus Lock
Focus lock can be used to change the composition after focusing, making it possible
to focus on a subject that will not be in a focus point in the final composition. It can
also be used when the autofocus system is unable to focus (pg. 55). Focus lock is
most effective when Single point, Dynamic area, or 3D-tracking (11 points) is
selected for Custom Setting a1 (AF-area mode; pg. 173).
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
(
J) appears in the viewfinder.
2
Lock focus.
AF-A and AF-C autofocus modes (pg. 54): With the
shutter-release button pressed halfway (q),
press the AE-L/AF-L button (w) to lock both focus
and exposure (an AE-L icon will be displayed in
the viewfinder). Focus will remain locked while
the AE-L/AF-L button is pressed, even if you later
remove your finger from the shutter-release
button.
AF-S autofocus mode (pg. 54): Focus will lock automatically when the in-focus
indicator appears, and remain locked until you remove your finger from the
shutter-release button. Focus can also be locked by pressing the AE-L/AF-L
button (see above).
3
Recompose the photograph and shoot.
Focus will remain locked between shots if you
keep the AE-L/AF-L button pressed (AF-A/AF-C) or
the shutter-release button pressed halfway
(AF-S), allowing several photographs in
succession to be taken at the same focus
setting.
Shutter-release button
AE-L/AF-L button