Center-Weighted Average Metering Center-weighted average metering gives special emphasis to the center of the frame, but also covers the surrounding area. Some photographers prefer this metering mode because it’s simpler and more predictable than multi-segment metering, which uses complex algorithms to sort through the data from all the different points of measurement.
Center-weighted metering is a good mode to select when you want to capture a brightly lit subject and be sure it’s exposed correctly compared with the surrounding areas. This is an excellent compositional technique because people’s eyes are always drawn to the brightest part of a photograph.
Unlike multi-segment metering, which interprets virtually the entire picture area, center-weighted metering does not attempt to identify and correct situations like backlighting. This means you have to be a bit more careful when using this type of metering. However, many experienced photographers prefer this mode because they can apply their own exposure compensation (+ and –) and know that the camera hasn’t automatically tried to do likewise. I used this mode for this picture of Dead Horse Point State Park in Utah.
Spot Metering Spot metering measures only a small area in the center of the frame. Typically, this area is a spot that’s only about two or three percent of the entire area of the picture (hence the term “spot” metering). When you have a select area of a picture that you want to precisely meter, and don’t want other areas of the scene to affect your exposure, such as this polar bear that I photographed in the sub-Arctic, this mode is the way to go. However, it can be a challenging metering mode to use because you really have to pay attention to exactly what it is measuring and interpret the brightness of the spot yourself.
The size of the spot varies from camera to camera, with high-end cameras usually having a smaller spot than entry-level cameras.