Canon EOS 5D Mark III Instruction Manual (en)

A Shooting with the LCD Monitor
Set [z4: Live View shoot.] to [Enable].
In the <
A> mode, it is displayed under 
Battery Life with Live View Shooting [Approx. number of shots]
The figures above are based on a fully-charged Battery Pack LP-E6 and CIPA 
(Camera & Imaging Products Association) testing standards.
With a fully-charged Battery Pack LP-E6, continuous Live View shooting is 
possible for approx. 1 hr. 30 min. at 23°C / 73°F.
Enabling Live View Shooting
At 23°C / 73°F
At 0°C / 32°F
Possible shots
Do not point the camera toward an intense light source, such as the sun 
on a sunny day or an intense artificial light source. Doing so may 
damage the image sensor or the camera’s internal components.
Cautions for using Live View shooting are on pages 217-218.
You can also focus by pressing the <p> button.
When flash is used, there will be two shutter sounds, but only one shot 
will be taken.
If the camera is not operated for a prolonged period, the power will turn 
off automatically as set with [52: Auto power off] (p.55). If [52: Auto 
power off
] is set to [Disable], Live View shooting will end automatically 
after 30 min. (camera power remains on).
With the stereo AV cable (provided) or HDMI cable (sold separately), you 
can display the Live View image on a TV (p.274, 277).