Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 793)

UI Magnification
You can magnify menu screens by double-tapping with two fingers. Double-tap again to
restore the original display size.
Magnification is also available on the Quick Control screen in viewfinder shooting, the
Custom Quick Control screen, and the electronic level screen.
1.
Select [ : UI magnification].
2.
Select [Enable].
Caution
Use camera controls when configuring menu functions with the display magnified.
Touch-screen operations are not supported.
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