Canon EOS 5Ds Instruction Manual page 82

A Fully Automatic Shooting (Scene Intelligent Auto)
Pressing the shutter button halfway does not focus on the
subject.
If the focus mode switch on the lens is set to <MF> (manual focus),
set it to <AF> (autofocus).
The shutter speed display is blinking.
Since it is too dark, taking the picture may result in a blurred subject
due to camera shake. Using a tripod or a Canon EX-series Speedlite
(sold separately, p.244) is recommended.
When the external flash was used, the bottom part of the
picture came out unnaturally dark.
If a hood is attached to the lens, it can obstruct the flash light. If the
subject is close, detach the hood before taking the picture with flash.
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