Auto ISO Sensitivity Control
Auto ISO sensitivity control lets the camera adjust ISO sensitivity automatically
                  if optimal exposure can not be achieved at the value selected by the user. 
Auto ISO sensitivity control can be very effective with some subjects. Here we’ll
                  examine how auto ISO sensitivity control can be used to photograph performers at a
                  small venue.
For photos of performers on stage, we recommend that you shoot
                  in manual exposure mode at shutter speeds of about 1/125 to 1/500 s and apertures
                  of about f/2.8 to 5.6 to allow for such factors as focus distance and subject motion.
The dizzying changes in lighting however make manual ISO sensitivity adjustment
                  extremely challenging. In cases like these, choosing manual exposure mode and selecting
                  On for Auto ISO sensitivity control allows auto
                  ISO sensitivity control to adjust exposure automatically in response to changes in
                  subject brightness without your having to adjust shutter speed or aperture.
               
In these two examples, shutter speed was set to a comparatively fast 1/320 s to allow
                  for the motion of the performers and aperture adjusted to f/4.5 to increase depth
                  of field. Exposure compensation was set to −0.7 to prevent overexposure when
                  performers were in the spotlight. Both photographs were taken from the same location,
                  but the camera automatically changed ISO sensitivity from ISO 1800 to 4500 to compensate
                  for changes in lighting between the two shots. The resulting exposure levels are close
                  enough that the results can be evened out using NEF (RAW) processing.
                  Manual exposure mode is recommended for shots of performers on stage; ISO sensitivity
                  control is also available in modes P, S, and A, but the varying shutter speed and
                  apertures make these modes difficult to use.
 When On
                  is selected for Auto ISO sensitivity control, you can also choose
                  the maximum ISO sensitivity that will be selected by the camera. Raising ISO sensitivity
                  too high can result in obvious mottling and other image noise, so take test shots
                  to determine an acceptable setting before choosing the maximum ISO sensitivity.
               
Maximum sensitivity
The maximum value for auto
                  ISO sensitivity can be selected using Maximum sensitivity.
Maximum sensitivity with
To choose the maximum ISO sensitivity
                  for photos taken using an optional flash unit, use Maximum sensitivity with  . Selecting Same as without flash
                  sets the maximum ISO sensitivity for flash photography to the value currently selected
                  for Maximum sensitivity.
. Selecting Same as without flash
                  sets the maximum ISO sensitivity for flash photography to the value currently selected
                  for Maximum sensitivity.
Minimum shutter speed
In exposure
                  modes P and A, sensitivity will only be adjusted if underexposure would result at
                  the shutter speed selected for Minimum shutter speed (in modes S and M, ISO sensitivity
                  will be adjusted for optimal exposure at the shutter speed selected by the user).
                  If Auto is selected, the camera will choose the minimum shutter speed based on the
                  focal length of the lens. Press  to exit when settings are complete.
 to exit when settings are complete.
Procedure

Select ISO sensitivity settings in the photo shooting menu, highlight Auto ISO sensitivity control and press
 .
.
                  
Highlight On and press
 (if Off
                     is selected, ISO sensitivity will remain fixed at the value selected by the user).
 (if Off
                     is selected, ISO sensitivity will remain fixed at the value selected by the user).
                  
Maximum sensitivity: 200–Hi 5
Maximum sensitivity with
 : 200–Hi 5
: 200–Hi 5Minimum shutter speed: 1/4000–30 s, or AUTO
Press
 to exit when settings are complete.
 to exit when settings are complete.
                  

 
                        