To fully interpret what your exposure meter tells you, you need to know which metering mode is active. The metering mode determines which part of the frame the camera analyzes to calculate the proper exposure. The metering mode affects more than the meter, however: It also determines the exposure settings that the camera selects for you when you shoot in the P, S, and A exposure modes as well as in the fully automatic exposure modes.
In the P, S, A, and M modes, you can adjust the metering mode by pressing the Metering button while rotating the Main command dial. An icon representing the current metering mode appears in the Information display, viewfinder, and Control panel, as shown in Figure 7-16.
Your camera offers three metering modes, represented by the icons you see in the margins here: