Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 876)

: Switch to Custom Shooting Mode
You can switch to registered Custom shooting modes ( ) by pressing the < > button
in shooting modes other than < >, < >, or < >. When you have added a [ ] to
[ ], [ ], and [ ] in [ 3 : Restrict shooting modes ], each press of the < >
button switches from to to to the current shooting mode.
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