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selector among the three-dozen (plus) focus points. That’s why CSM #a6 lets you switch
the D7000 to a more widely spaced set of 11 focus zones that you can select quickly.
(Learn how to do that in Chapter 9.) Figure 5.10 shows the distribution of the active
focus points when in 39-point mode (left) or 11-point mode (right).
As the camera collects contrast information from the sensors, it then evaluates the data
to determine whether the desired sharp focus has been achieved. The calculations may
include whether the subject is moving, and whether the camera needs to “predict” where
the subject will be when the shutter release button is fully depressed and the picture is
taken. (Predictive focus tracking kicks in when the camera is set to AF-C continuous
autofocus, or when you’re using AF-A and the D7000 shifts from AF-S to AF-C. I’ll
explain these modes in more detail in the next section.)
The speed with which the camera is able to evaluate focus and then move the lens ele-
ments into the proper position to achieve the sharpest focus determines how fast the
autofocus mechanism is. Although your D7000 will almost always focus more quickly
than a human, there are types of shooting situations where that’s not fast enough. For
example, if you’re having problems shooting sports because the D7000’s autofocus sys-
tem manically follows each moving subject, a better choice might be to switch autofo-
cus modes or shift into manual and prefocus on a spot where you anticipate the action
will be, such as a goal line or soccer net. At night football games, for example, when I
am shooting with a telephoto lens almost wide open, I often focus manually on one of
the referees who happens to be standing where I expect the action to be taking place
(say, a halfback run or a pass reception). I also use trap focus, which is a technique dis-
cussed in a sidebar later in this chapter.
Choosing Autofocus Point Selection Mode
The D7000 has only three different focus point selection modes. I’m going to describe
each of the three modes, and explain how to use them. You can set any of the three point
selection modes: hold down the center button of the focus mode selector switch on the
front of the camera (under the lens release button) to the AF position. Then, hold down
Chapter 5 ■ Mastering Autofocus Options 145
Figure 5.10 The D7000 can use a dense set of 39 focus points (left), or a wider array of 11 points (right).