Nikon D300 - Manual (Page 138)

112
Z
Autoexposure (AE) Lock
Use autoexposure lock to recompose photographs after metering
exposure.
1
Select center-weighted or
spot metering (pg. 100).
Matrix metering will not
produce the desired results
with autoexposure lock. If
using center-weighted
metering, select the center
focus point with the multi
selector (pg. 66).
2
Lock exposure.
Position the subject in the selected
focus point and press the shutter-
release button halfway. With the
shutter-release button pressed halfway
and the subject positioned in the focus
point, press the AE-L/AF-L button to lock
exposure (and focus, except in manual
focus mode). Confirm that the in-focus
indicator (
I) appears in the viewfinder.
While exposure lock is in effect, an AE-L
indicator will appear in the viewfinder.
Metering selector
Shutter-release
button
AE-L/AF-L button