Canon EOS 5D MARK III Instruction Manual page 14

Using the Self-timer
If you will not look through the viewfinder when you press the shutter button.
attach the eyepiece cover (p.185). If stray light enters the viewfinder when
the 0icture is taken, it may throw off tne exposure.
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The <_._2 > enables you to shoot while not touching the camera
mounted on a tripod. This prevents camera shake while you shoot still
lifes or bulb exposures.
r_, After taking self-timer shots, playing back the image (p.244_ to check
focus and exposure is recommended.
When using the self-timer to shoot only yourself, use focus lock (p.67 • on
an object at about the same distance as where you will stand.
To cancel the self-timer after it starts, press the < AF" DRIVE > button.
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