Nikon D3 User Manual page 157

A
Metered Area
In spot metering, exposure will be locked at the value metered in a 4-mm
(0.16 in.) circle centered on the selected focus point. In center-weighted
metering, exposure will be locked at the value metered in the center of
the viewfinder (the default area for center-weighted metering is shown by
the 12-mm circle in the viewfinder).
A
Adjusting Shutter Speed and Aperture
While exposure lock is in effect, the following settings can be changed
without altering the metered value for exposure:
Exposure mode
e
f
g
The new values can be confirmed in the viewfinder and top control panel.
Note that the metering method can not be changed while exposure lock
is in effect (changes to metering take effect when the lock is released).
A
See Also
If [On] is selected for Custom Setting c1 ([Shutter-release button AE-L], pg.
317), exposure will lock when the shutter-release button is pressed
halfway. For information on changing the role of the AE-L/AF-L button, see
Custom Setting f6 ([Assign AE-L/AF-L button], pg. 338).
Shutter speed and aperture (flexible program; pg. 119)
Settings
Shutter speed
Aperture
Z
131