I'm using a macbook pro 8,1. When I use the brightness keys on the keyboard, decreasing the brightness works until it reaches the lowest brightness level. At that point (when on the lowest level), the brightness is something like 70 or 80% instead of 0-10% (or whatever it usually is). All the other levels are fine.

How can I adjust/calibrate these brightness controls?

PS: I'm currently using 12.04 but I've had the same issue no later than 11.10 (and I'm fairly confident it was present in 11.04 as well).

UPDATE: If I go to System Settings and select "Brightness and Lock" the exact same thing happens, but there is more fine grained control of the brightness. It goes to completely black when the dial is about 10% from the left edge. When it passes that point, anywhere inside that left 10% appears to be about 70 - 80% brightness (there's no change regardless of where the dial is in this section).