Exposure and AF Points
Many cameras tie the area used for spot metering to the currently selected focus point. This allows you to use the spot meter on the same area where you are focusing, which makes sense because theoretically it is the most important part of the image. For example, I want to use spot metering on the motocross rider against the bright blue sky. The combination of the bright sky and dark-clothed rider makes for a great opportunity to use the spot metering, but I want to make sure that the rider isn’t right in the middle of the frame. In Figure 4.10, you can see that placing the focus point on the helmet lets the camera spot meter on the same point on which I am focusing. This allows me to not only focus on the most important part, but also get the exposure reading from the same spot.
Figure 4.10 The AF point and the spot metering are both tied to the same area, shown in red.
Nikon D4 • ISO 400 • 1/2000 sec. • f/5.6 • 70–200mm f/2.8 lens