To interpret what the exposure meter tells you, you need to be aware of the current Metering mode on your Nikon D5500, which determines which part of the frame the camera analyzes to calculate exposure. The Metering mode affects the meter reading in M mode as well as the exposure settings that the camera chooses in the fully automatic shooting modes as well as in the P, S, and A modes.
The Information display and Live View screen both contain a symbol representing the current metering mode. You can choose from three modes, described in the following list.
Matrix: The camera analyzes the entire frame and then selects an exposure that’s designed to produce a balanced exposure.
Your camera manual refers to this mode as 3D Color Matrix II, which is the label that Nikon created to describe the specific technology used in this mode.
Center‐weighted: The camera bases exposure on the entire frame but puts extra emphasis — or weight — on the center of the frame. Specifically, the camera assigns 75 percent of the metering weight to an 8mm circle in the center of the frame.
Spot: In this mode, the camera bases exposure entirely on a circular area that’s about 3.5mm in diameter, or about 2.5 percent of the frame. The location used for this pinpoint metering depends on an autofocusing option called the AF‐area mode. This option determines which of the camera’s focus points the autofocusing system uses to establish focus. Here’s how the setting affects exposure metering:
If you choose the Auto Area mode, in which the camera chooses the focus point for you, metering is based on the center focus point.
If you use any of the other AF‐area modes, which enable you to select a specific focus point, the camera bases metering on that point.
Because of this autofocus/autoexposure relationship, it’s best to switch to one of the AF‐area modes that allow focus‐point selection when you want to use spot metering. In Auto Area mode, exposure may be incorrect if you compose your shot so that the subject isn’t at the center of the frame.
As an example of how Metering mode affects exposure, below is the same image captured in each mode. In the matrix example, the bright background caused the camera to select an exposure that left the statue quite dark. Switching to center‐weighted metering helped somewhat but didn’t quite bring the statue out of the shadows. Spot metering produced the best result as far as the statue goes, although the resulting increase in exposure left the sky a little washed out.
Matrix metering is the default setting, and you can change the Metering mode only in the P, S, A, and M exposure modes. The only way to adjust the setting is via the Information display or Live View control strip.
You activate the strip by pressing the i button or tapping the i symbol on the monitor.
In theory, the best practice is to check the Metering mode before you shoot and choose the one that best matches your exposure goals. But that’s a bit of a pain, not just in terms of having to adjust yet one more capture setting but also in terms of having to remember to adjust one more capture setting.
Here’s some advice: Until you’re really comfortable with all the other controls on your camera, just stick with the default setting, which is matrix metering. That mode produces good results in most situations, and after all, you can see in the monitor whether you disagree with how the camera metered or exposed the image and simply reshoot after adjusting the exposure settings to your liking. This option makes the whole Metering mode issue a lot less critical than it is when you shoot with film.
The one exception might be when you’re shooting a series of images in which a significant contrast in lighting exists between subject and background. Then, switching to center‐weighted metering or spot metering may save you the time spent having to adjust the exposure for each image.
