Nikon FM2 - Manual (Page 29)

Exposure display
The LED exposure indicator iamps can be seen on the right side
of the viewfieid frame within the viewfinder. The shutter speed
number and f/number in use are aiso visibie. The LED exposure
display indicates exposure five ways, as shown in the table
below, in accordance with the conditions of each exposure.
Overexposure by more than 1 stop
Overexposure by 1/5 to 1 stop
Correct exposure
Underexposure by 1/5 to 1 stop
Underexposure by more than 1 stop
As correct exposure is approached, the LED exposure display
inside the viewfinder is liable to change rapidly and easily within
the very narrow range, so it is important to turn the lens aper­
ture ring and shutter speed dial carefully. Although intermediate
shutter speeds cannot be used, intermediate lens apertures
can—just turn the aperture ring for fine adjustment.
Note: When the shutter speed dial is set at B (bulb), the LED exposure
display inside the viewfinder is turned off.
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