Nikon D3body - D3 Body 12mp FX Digital SLR Camera Technical Manual page 18

Exposure
Choose the following ISO sensitivity settings:
ISO sensitivity auto
control: On
In this example, ISO sensitivity will automatically be raised
to a maximum of ISO 6400 if optimal exposure can not be
achieved at ISO 200. In modes
raised only if the shutter speed required for optimal exposure
would be slower than
1
speed of /
500
6400).
18
ISO sensitivity: 200
Maximum sensitivity:
6400
1
/
500
s would still result in underexposure at ISO
Auto ISO Sensitivity Control
e and
s (slower speeds will be used if a
Minimum shutter
speed: 1/500 s
g , sensitivity will be