Hi all in the manual the only way to activate the e-level in viewfinder via the DOF button. Most of us use the DOF frequently. As this button seems to have only one function (no double task in connection with another button) this option is out for me as I need, or would use both equally often. Is there any other option to activate electronic level in the viewfinder, maybe even via firmware??
You can also map the VF electronic level to either the M-Fn or M-Fn2 buttons in addition to using the DOF Preview button. Mapping DOF Preview to the M-Fn2 button is another option as well.
It's all on the chart on pages 336-37 of the original EOS 1D X Instruction Manual. (Note that the 1D X Manual for firmware version 1.1.0 places it on pages 340-341)