Digital cameras offer choices of metering patterns. Depending on the model and manufacturer, the names for similar choices may be different and the number of choices vary as well.
Evaluative or Color Matrix Metering Mode
These choices are similar. They divide up the image into many sectors which are analyzed by the camera using complicated algorithms to determine the exposure. The camera compares the brightness of the subject and the background, compensates for backlighting, and other variables. If you are going to use automatic exposure, this sophisticated mode is an excellent choice.
Center-Weighted Averaging
This metering mode meters the entire scene, but puts emphasis on the middle of the image because that is most likely where the subject is. It works well when bright sky is near the top of the frame because the sky doesn’t influence the meter much. Center-weighted averaging works okay, but evaluative or color matrix metering really does a better job handling most situations.
Partial Metering
This mode uses the center of the frame to determine exposure. It is most effective when bright areas surround the frame. Since the meter only considers the center of the frame, it ignores white clouds at the top of the frame that might cause the camera to underexpose the main subject.
Spot Metering
This metering mode measures the light only from a small area in the middle of the frame which makes up about 2–3% of the viewfinder. It is the most precise way to meter, but requires a good deal of practice and study to really master. You must meter carefully, learn to judge reflectance values, and know how to compensate the exposure. Spot metering is the best way to expose slide film, but may be overly precise for many digital photographers due to the slightly wider dynamic range digital can capture and the use of the highlight alert and histogram metering aids.
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