Nikon Camera F3AF - Manual (Page 42)

To match the convenience of autofocus, the Nikon
F3AF features aperture-priority auto exposure. All
you do is set the camera at A (Auto) and fire away.
Light is automatically measured through the lens
at full aperture, and the correct shutter speed Is
electronically determined to match the aperture in
use. The F3AF also lets you select the shutter
speed manually for complete creative control.
Because the fast-reacting SPD metering cell Is
located in the camera body below the reflex mirror
@, you have full metering capabilities even with
an interchangeable viewfinder attached. Meter­
ing Is centerwelghted; 80% of Its sensitivity Is
concentrated In the 12mmi^ center spot of the
focusing screen, while the remaining 20 % is distri­
buted over the rest of the screen. To get the cor­
rect exposure, center the main subject in the finder.
There are three factors involved In determining
exposure: film speed, aperture, and shutter speed.
All must be set correctly to get the proper exposure.