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.
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.
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.