Nikon D5 User Manual page 164

A
Metered Area
In spot metering, exposure will be locked at the value metered at the
selected focus point (0 129). In center-weighted metering, exposure
will be locked at the value metered in a 12-mm circle in the center of the
viewfinder.
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Adjusting Shutter Speed and Aperture
While exposure lock is in effect, the following settings can be adjusted
without altering the metered value for exposure:
Exposure mode
P
S
A
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.
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See Also
If On (half press) is selected for Custom Setting c1 (Shutter-release
button AE-L, 0 300), exposure will lock when the shutter-release
button is pressed halfway.
Z
142
Shutter speed and aperture (flexible program; 0 133)
Setting
Shutter speed
Aperture