Canon EOS 5D Mark III Instruction Manual page 366

Troubleshooting Guide
When I shoot still photos during movie shooting, the movie shooting stops.
To shoot still photos during movie shooting, using a CF card

compatible with UDMA transfer rates is recommended.
Setting a lower image quality for still photos and shooting fewer

continuous still photos can also resolve the problem.
Time code is off.
Shooting still photos during movie shooting will cause a discrepancy

between the actual time and time code. When you want to edit a movie
using time code, it is recommended not to shoot still photos during
movie shooting.
Operation Problems
I cannot change the setting with <6>, <5>, or <9>.
Set the <R> switch to the left (lock release, p.47).

Check the [82: Multi function lock] setting (p.319).

The camera button/dial's function has changed.
Check the [82: Custom Controls] setting (p.321).

Display Problems
The menu screen shows few tabs and options.
In the <A> mode, only certain menu tabs and options are displayed.

Set the shooting mode to <d/s/f/a/F> (p.51).
The file name's first character is an underscore ("_").
Set the color space to sRGB. If Adobe RGB is set, the first character

will be an underscore (p.158).
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