Nikon D70S - Manual (Page 86)

76
Taking Photographs—Exposur
e
Exposure Mode
When the mode dial is rotated to P, S, A, or M, the user can set shutter speed
and aperture as described on the following pages.
CPU Lenses
When using a CPU lens equipped with an aperture ring, lock the aperture ring at the
min i mum aperture (highest f/-number). At other settings, the shutter release will be
dis abled and a blinking
will appear in the aperture displays in the top control
panel and viewfi nder. Type G lenses are not equipped with an aperture ring.
Non- CPU Lenses
Non-CPU lenses can only be used in mode M, when aperture can be adjusted manually
using the lens aperture ring. In other modes, the shutter-release will be disabled and a
blinking
will appear in the control panel and viewfi nder aperture displays.
Depth-of-Field Preview
To preview the effects of aperture, press and hold the
depth-of-fi eld preview button. If a CPU lens is attached,
the lens will be stopped down to the aperture value
se lect ed by the cam era (P and S modes) or the val ue
cho sen by the user (A and M modes), al low ing depth of
fi eld to be previewed in the viewfi nder (depth-of-fi eld
preview is not available with non-CPU lenses).
5—ISO Auto ( 142)
When On is selected for Custom Setting 5 (ISO auto), the camera automatically varies
sensitivity in the range 200–1600 (ISO equivalent) to help ensure optimum ex po sure
and fl ash level. In P and A modes, the camera adjusts sensitivity when the shutter
speed needed to obtain optimum exposure would be faster than
1 /
8000
s or slower than
a specifi ed value (shutter speed may drop below the specifi ed value if optimal exposure
can not be achieved at ISO 1600 equivalent). Otherwise the camera adjusts sensitiv-
ity when the limits of the camera exposure me ter ing sys tem are exceeded (mode S)
or when optimum exposure can not be achieved at the shutter-speed and aperture
selected by the user (mode M).
When sen si tiv i ty is al tered from the value se lect ed by
the user, ISO AUTO fl ashes in the control panel and
viewfi nder. In the camera photo information display for
pictures taken at altered sensitivities, the ISO value will
be displayed in red. Note that noise is more likely to ap-
pear in pho to graphs taken at higher sen si tiv i ties.