Nikon D300 User Manual page 696

OK button on the final screen, without changing anything.
Figure 10-11 shows Direct sunlight as an example.
Note that the Fluorescent selection allows you to choose one
of seven different light sources, covering a wide spectrum.
If you choose to fine-tune any of the color temperature
settings after you have selected one of the preset WB values,
the color box in the last screen of Figure 10-11 allows you to
do so by mired clicks. Each press of the Multi Selector in a
given direction is equal to 5 mired in that direction—up is
green (G), down is magenta (M), left is blue (B), right is
amber (A).
If you aren't familiar with adjusting the preset's default color
temperature, or don't want to change it (most won't), then
simply press the OK button without moving the little square
from the center. If you've accidentally moved it, simply move
it back with the Multi Selector until it's in the middle again,
then press the OK button. That will select the preset WB
value without modifying its default value (see Method 1 for a
list of the preset WB default values).
That is all there is to selecting a WB preset from within the
Shooting Menu system. The only difference between this
method and Method 1 is that this method allows you to
fine-tune the color temperature values (Figure 10-11, image
3). I normally do not use
Method 2 since Method 1 allows me to select a preset WB
value without accidentally modifying its default color
temperature, and it doesn't require me to use the menus.
I find that Method 1 is much faster since I am using external
camera controls, and it takes only seconds to set the values or
even do a PRE reading of ambient light.
696