Canon 5D Mark III User Manual (en)

Movie Shooting Cautions
White <s> and Red <E> Internal Temperature Warning Icons
If the camera’s internal temperature increases due to prolonged movie 
shooting or a high ambient temperature, a white icon <s> will appear. 
Even if you shoot a movie while this icon is displayed, the movie’s image 
quality will hardly be affected. However, if you shoot still photos, the 
image quality of the still photos may degrade. You should stop shooting 
still photos for a while and allow the camera to cool down.
If the camera’s internal temperature further increases while the white 
icon <s> is displayed, a red icon <E> may start blinking. This blinking 
icon is a warning that movie shooting will soon end automatically. If this 
happens, you will not be able to shoot again until the camera’s internal 
temperature decreases. Turn off the power and let the camera rest for a 
Shooting a movie at a high temperature for a prolonged period will cause 
the <s> and <E> icons to appear earlier. When you are not shooting, 
turn off the camera.
Recording and Image Quality
If the attached lens has an Image Stabilizer, the Image Stabilizer will 
operate at all times even if you do not press the shutter button halfway. 
The Image Stabilizer consumes battery power and may shorten the total 
movie shooting time or decrease the number of possible shots. If you 
use a tripod or if the Image Stabilizer is not necessary, you should set the 
IS switch to <2>.
The camera’s built-in microphone will also pick up camera operation 
noise. Using a commercially-available external microphone can prevent 
(or reduce) these noises from being recorded.
Do not connect anything other than an external microphone to the 
camera’s external microphone IN terminal.
Autofocusing during movie shooting is not recommended since it may 
momentarily throw the focus far off or change the exposure.