Nikon D300 Complete Manual page 323

V1.02
balance is very important to me. Unfortunately, "dead-on"
might not be one of the labeled white balance settings and
you'll have to adjust the fine tuning to get there. But knowing
what to dial in takes experience in analyzing light. Even
people shooting standard reference cards need some training
to recognize color shifts.
For example, let's say that I walked into a room that was lit
with Incandescent lights that were known to be 3000K. You
might think that I'd just dial in Incandescent (which is
balanced for 3000K) and be done with white balance.
However, I long ago learned to look at the color of the walls,
since they'll be reflecting that light. What if the walls were a
slight yellow color? Well, I'd use the fine tuning attribute to
move the black dot away from that color in the fine tuning
grid. Why? Because the walls will add a yellow reinforcement
to the colors and I need to add in color to balance that out.
If you use the camera's WB button with the Front Command
dial to "fine tune" the white balance, you use only the color
temperature adjustment from the white balance fine tuning
system (blue/amber axis). Nikon only provides cryptic labels
for indicating the fine tuning changes with this method (whole
numbers from a1 to a6 and from b1 to b6. According to
Nikon, each increment represents a 5 MIRED shift in color
97
temperature . These correspond (very) roughly to the old -3
to +3 white balance tuning options used in previous Nikon
bodies.
Here's how these numbers influence each of the white
balance settings:
97 My Nikon Field Guide, published in 1998 was I believe the first non-academic
work to use MIRED to calculate color shifts.
Thom Hogan's Complete Guide to the Nikon D300 Page 323