Af Activation; Custom Setting A5 (D300S And D) - Nikon D300 User Manual

If you turn off Focus tracking with lock-on, you'll have a
camera that doesn't know how to keep its attention on the
subject you are trying to photograph if something interferes.
When using Dynamic-area AF or Auto-area AF modes, I call
turning off Focus tracking with lock-on "focus roulette!"
Configuring Custom setting a4 is not difficult. However,
you'll need to decide just how long you want your camera to
lock on to a subject before it decides that the subject is no
longer available.
My Recommendation: I leave Focus tracking with lock-on
enabled at all times. When I'm tracking a moving subject, I
don't want my camera to be distracted by every bright object
that gets in between me and the subject. Nikon gives us
variable focus lock time-outs so we can change how long the
camera will keep seeking the old subject, when we switch to a
new one. I suggest you play around with this function until
you fully understand how it works. Watch how long the
camera stays locked on one subject's area before an intruding
object grabs its attention. This is one of those functions that
people either love or hate. Personally, I find it quite useful for
my type of photography. Try it and see what it does for you.

AF Activation

Custom setting a5 (D300S and D300)
(User's Manual – D300S page 266; D300 page 271)
AF activation allows you to choose whether you want the
Shutter-release button to cause the camera to autofocus. If
you leave this setting at the factory default, the AF system
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