Nikon FM2 - Manual (Page 30)

CONTROLS IN DETAIL —continued
Metering range of exposure meter
When there is a proper combination of lens aperture and shutter
speed, o lights up, indicating correct exposure. This sign will not
light up when the aperture and shutter speed combination is not
suitable for correct exposure. Also, if the combination of aper­
ture and shutter speed is improper for the brightness of the
subject, the exposure meter will not give an indication for cor­
rect exposure even if you vary the neighboring settings within
a very narrow range. You should try altogether different com­
binations of aperture and shutter speed. If you still fail to obtain
an indication for correct exposure, then subject brightness is
probably beyond the metering range of the exposure meter. It
is necessary to illuminate the subject or to use an ND (neutral
density) filter to adjust brightness. Note that in full-aperture
measurement, the range of brightness that can be measured
by the meter varies with the maximum f/number of the lens
in use, as follows:
With a 50mm f/1.4 lens (1 sec. at f/1.4 and 1/4000 sec. at f/8)
and ASA/ISO 100 film, the EV range is from EV 1 to EV 18.
With a 135mm f/2.8 lens (1 sec. at f/2.8 and 1/4000 sec. at f/16)
and ASA/ISO 100 film, the EV range is from EV3 to EV20
22