Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 217)

6.
Set [Continue Mult-exp].
Select an option, then press < >.
With [ 1 shot only ], multiple-exposure shooting will be canceled
automatically after the shooting ends.
With [ Continuously ], multiple-exposure shooting continues until the
setting in step 2 is set to [ Disable ].
7.
Shoot the first exposure.
When [ On:Func/Ctrl ] is set, the captured image will be displayed.
The < > icon blinks.
You can check the number of remaining exposures, as displayed at
right in the viewfinder or on the screen (1).
Pressing the < > button enables you to view the captured image
( ).
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