V1.02
Thom Hogan’s Complete Guide to the Nikon D300
Page 391
turning on
Focus point
using
Display mode
on the
PLAYBACK menu and then navigating to the page that
shows that information during image playback.
There’s good news, too:
•
Focusing can occur over a large area.
Only the D2 series
can claim to cover as wide an area of the image frame as
the D300, and those earlier cameras had gaps in the
middle of their coverage that the D300 doesn’t have. The
D300 can focus on subjects far more off-center than can
its predecessor, the D200.
•
Low light performance covers a wider area.
The fifteen
crossed sensors in the middle of the autofocus sensor
array cover a wider area than those in the D200 or any
other camera Nikon has made. Even the D2 series, which
had nine very large crossed sensors scattered over the
frame didn’t quite cover as much contiguous area for low-
light performance as the D300.
•
Focusing is integrated with metering.
The reason why Auto
Area is so good at recognizing people in a frame has to do
with the integration with the metering sensor, which
provides the color information that tells the autofocus
system where skin tones occur in the frame. Likewise, if
you select 51point 3D tracking, the meter provides pattern
recognition information to the autofocus sensors, which
helps them determine where in the scene your subject has
moved.
One important thing to note: in terms of user control, the
Autofocus Area settings range from total (bottom selection on
the control switch: Single Point) to none (top selection on the
control switch: Auto). If you find that you don’t have enough
control of the sensor area used for focusing, try using the
Autofocus Area mode setting immediately below the one
you’re using!
Trap Autofocus
If you’ve used a Nikon film SLR, you may have encountered a
special autofocus mode called “trap autofocus.” On some
