Nikon D330018-55VR User Manual (en)

The Shooting Menu: Shooting Options
❚❚ Auto ISO Sensitivity control
If Off is chosen for Auto ISO sensitivity control in PSA, and M 
modes, ISO sensitivity will remain fixed at the value selected by 
the user (
0 95). When On is chosen, ISO sensitivity will 
automatically be adjusted if optimal exposure can not be 
achieved at the value selected by the user. The maximum value 
for auto ISO sensitivity can be selected using the Maximum 
 option in the Auto ISO sensitivity control menu 
(choose lower values to prevent noise (randomly-spaced bright 
pixels, fog, or lines), but note that if the ISO sensitivity selected 
by the user is higher than that chosen for Maximum sensitivity
the value selected by the user will be used instead; the minimum 
value for auto ISO sensitivity is automatically set to ISO 100). In 
modes P and A, sensitivity will only be adjusted if underexposure 
would result at the shutter speed selected for Minimum shutter 
–1 s, or Auto; in modes S and M, sensitivity will be 
adjusted for optimal exposure at the shutter speed selected by 
the user). If Auto (available only with CPU lenses) is selected, the 
camera will choose the minimum shutter speed based on the 
focal length of the lens. Slower shutter speeds will be used only 
if optimum exposure can not be achieved at the ISO sensitivity 
value selected for Maximum sensitivity.
When On is selected, the viewfinder 
shows ISO-AUTO and the information 
display ISO-A. These indicators flash when 
sensitivity is altered from the value 
selected by the user.