Nikon D100 - Manual (Page 96)

Taking Photographs—Exposur
e
Exposure
84
Autoexposure Lock
When center-weighted metering is used, an area in the center of the frame is
assigned the greatest weight when determining exposure. Similarly, when
spot metering is used, exposure is based upon lighting conditions in the cur-
rently selected focus area. If your subject is not in the metered area when the
picture is taken, exposure will be based on lighting conditions in the back-
ground, and your main subject may be under- or over-exposed. To prevent
this, use autoexposure lock:
1 Select center-weighted or spot metering. If us-
ing center-weighted metering, select the cen-
ter focus area with the multi selector (
64).
2 Position the subject in the selected focus area and press the shutter-release
button halfway. Keeping the shutter-release button pressed halfway and
your subject positioned in the focus area, press the AE-L/AF-L button to
lock exposure (and focus, except in manual focus mode). Confirm that the
in-focus indicator (●) appears in the viewfinder.
While exposure lock is in effect, an EL indicator will appear in the viewfinder.