Nikon D5500 Product Manual - Page 266

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. A Maximum Sensitivity/Minimum Shutter Speed When auto ISO sensitivity control is enabled, the ISO sensitivity and shutter speed graphics in the information display show the maximum sensitivity and minimum shutter speed. Minimum shutter speed Maximum sensitivity A Auto ISO Sensitivity Control Noise (randomly-spaced bright pixels, fog, or lines) is more likely at higher sensitivities. Use the High ISO NR option in the shooting menu to reduce noise (0 244). Note that ISO sensitivity may be raised automatically when auto ISO sensitivity control is used in combination with slow sync flash modes (available with the built-in flash and the optional flash units listed on page 323), possibly preventing the camera from selecting slow shutter speeds. Auto ISO sensitivity control is available only in i-TTL flash control mode (0 259, 325); in other modes, the value selected for ISO sensitivity will be used for pictures taken with the built-in flash or optional flash units. 242 C The Shooting Menu: Shooting Options