Canon EOS-1D X Mark III Af Setting Manualbook page 84

Electronic shutter
High-speed continuous shooting at up to
approximately 20 fps is possible with AF/
AE tracking during electronic shutter
shooting.
Select [Electronic] from the [
use the electronic shutter during Live View shooting.*This
setting is very effective for stage photography and wildlife
photography that are sensitive to sound. High-speed
continuous shooting at a maximum speed of approximately
20 fps is possible, so you can capture the moment from a
variety of movements. When shooting sports such as golf
where consideration for sound is important recording can
be performed without missing a decisive moment by
starting continuous photography right before the start of
a golfer's swing.
Please note that depending on the subject, rolling shutter
distortion may occur due to the electronic shutter.
* Depending on the setting, aperture operating noise may occur.
4] tab [Shutter mode] to
Shooting with the electronic
shutter is recommended
where sound is a concern.
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