Nikon D1 Manual page 55

Spot metering: The camera measures light only in a circle 4mm
(0.15˝) in diameter and centered on the current focus area. The area
metered occupies approximately two percent of the entire frame.
This method can be used with back-lit subjects or on other occasions
when the background is much darker or much brighter than your
subject.
As a rule, spot metering measures light in the current focus area,
ensuring that your subject is properly exposed. When closest-
subject priority is used with dynamic AF area selection, or when a
non-CPU lens is attached, light will be measured in the center focus
area only.
To choose a metering method, hold the metering
selector lock release down and rotate the metering
selector to the desired setting.
Tip
Some lenses do not support one or more of the above metering systems. See
"Technical Notes: Compatible Lenses" for more information.
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Camera Settings: Metering