Canon EOS 5D Mark III Instruction Manual (en)

Basic Operation
Turn on (9)/off the LCD panel 
illumination by pressing the <U> button. 
During a bulb exposure, pressing the 
shutter button completely will turn off the 
LCD panel illumination.
After you press the <
B> button a 
number of times, the shooting settings 
will be displayed.
With the shooting settings displayed, you 
can turn the Mode Dial to see the 
settings for each shooting mode (p.343).
Pressing the <Q> button enables Quick 
Control of the shooting settings (p.49).
Press the <
B> button again to turn 
off the display.
 LCD Panel Illumination
Displaying Shooting Settings