Nikon D100 Product Manual - Page 88

Exposure Exposure Mode Your choice of exposure mode determines how the camera sets shutter speed and aperture when adjusting exposure. Four modes are available: auto multi program (P), shutter-priority auto (S), aperture-priority auto (A), and manual (M). Taking Photographs-Exposure CPU Lenses (All Exposure Modes) If you are using a CPU lens equipped with an aperture ring, the aperture ring must be set to the minimum aperture (highest f/-number). At other settings, the shutter release will be disabled and a blinking will appear in the aperture displays in the control panel and viewfinder. Type G lenses are not equipped with an aperture ring. Depth-of-Field Preview (All Exposure Modes) To get an idea of how your photograph will look at the current aperture setting, press and hold the depth-offield preview button. The lens will be stopped down to the aperture value selected by the camera in auto multi program or shutter-priority auto, or the value chosen by the user in aperture-priority auto or manual exposure mode, allowing you to preview depth of field in the viewfinder. 3-ISO Auto ( 148) When ON is selected for Custom Setting 3 (ISO Auto), the camera automatically varies sensitivity in the range 200-1600 (ISO equivalent) to help ensure optimum exposure when the limits of the camera exposure metering system are exceeded at the sensitivity selected by the user. In programmed auto, this helps ensure that the correct exposure can be achieved with subjects that would otherwise be too bright or too dark. In other exposure modes, it helps ensure correct exposure at the shutter speed and/or aperture selected by the user. When sensitivity is altered from the value selected by the user, the viewfinder exposure-mode indicator (P, S, A, or M) will flash and the sensitivity indicator in the viewfinder (ISO) will be displayed in red. In the camera photo information display for pictures taken at altered sensitivities, the ISO value will also be displayed in red. Note that noise is more likely to appear in photographs taken at higher sensitivities. ON can not be selected for ISO Auto when sensitivity is set to or ; similarly, or can not be selected when ISO Auto is on. If a flash is used when ISO Auto is on, ISO will be fixed at the value selected by the user. 76