V1.02
Thom Hogan’s Complete Guide to the Nikon D300
Page 395
Now your camera is configured to autofocus
only
when you
press the
AF-ON
button. This provides you with the following
abilities:
•
Focus and reframe.
Focus on your subject using the
AF-
ON
button, let go of the button, then reframe. Focus stays
where it was when you let go of the
AF-ON
button.
•
Track focus.
Just hold the
AF-ON
button in while
shooting. Focus will be performed as usual. This takes a
bit of dexterity, as you have to hold the
AF-ON
button in
at the same time as pressing the shutter release.
•
Manually focus.
With most AF-S lenses, just twist the
focus ring. On other lenses, move the lens’ focus switch to
the
M
position first.
This means that the primary control you change—if you make
any change—is only the Autofocus Area selector switch on
the back of the camera. Switch to Single Point for focus-and-
reframe, to Dynamic Area or Auto Area for tracking focus,
depending upon the subject. (Note that you can assign
Dynamic AF Area settings to the
Fn
button on the front of the
camera via Custom Setting #F4.)
Using this technique takes practice, so don’t expect to make
those settings and rush out and take perfect pictures a few
minutes later. However, with practice it becomes second
nature and relatively easy to control your focus in most
situations without having to make multiple settings changes.
Adjusting Your Lenses
Nikon has provided a method of fine-tuning the autofocus
performance of individual lenses with the D300. This, of
course, immediately brings up the question of why you might
need to do that—aren’t all new lenses perfect right from the
factory?
Yes and no. The phase detection autofocus system used by
Nikon in the DSLR cameras is generally accurate, but not
perfect. You may be surprised to learn that there are quite a
