Canon EOS 5D Mark III Instruction Manual page 258

Q Quick Control During Playback
To rotate an image, set [51: Auto rotate] to [OnzD]. If [51: Auto rotate]
is set to [OnD] or [Off], the [b Rotate image] setting will be recorded to
the image, but the camera will not rotate the image for display.
Pressing the <Q> button during the index display will switch to the
single-image display and the Quick Control screen will appear. Pressing
the <Q> button again will return to the index display.
For images taken with another camera, selectable functions may be
limited.
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