Nikon D300 User Manual page 300

and you want to force it to add 1/2 step exposure, you simply
add 3/6 EV to the compensation system for that metering
system. (Remember basic fractions—where 1/2 equals 3/6?)
This works like the normal compensation system, except it
only allows you one EV of compensation. As screen 3 of
Figure 4-25 shows, an ominous looking warning appears,
telling you that your camera will not show a compensation
icon, as it does with the normal +/- Exposure compensation
button, when you use the metering fine-tuning system. This
simply means that while you have this fine-tuning system
dialed in for your light meter, the camera will not remind you
that it is fine-tuned by showing you a compensation icon. If it
did turn on the compensation icon (+/- on the Control panel
and in the Viewfinder), then how could it show you the same
icon when you are using normal compensation at the same
time as meter fine-tuning?
This light meter fine-tuning only applies to the Custom
setting bank you are currently working with. If you are
working in bank A, banks B, C, and D are not changed.
Here are the screens and steps to fine-tune the metering
system's exposure (Figure 4-25):
300