Depends upon what you need. Mono? Stereo?
The User Manual on page 453 mentions that "Most external microphones compatible with 3.5mm mini-jacks can be used."
For a 3.5mm mini-jack mic, I've been really liking the Azden SMX-30 stereo mic. It is powered by two AAs and so far, when its power switch is set to auto, all the following equipment has triggered it to turn on/off as the equipment is turned on/off: Vixia HF G50, EOS 5D Mark IV, EOS C70.
I would recommend mics that offer you at least some low pass and level controls.
Note that you also should not pick up a mic that would require phantom power.
--
Ricky
Camera: EOS 5D IV, EF 50mm f/1.2L, EF 135mm f/2L
Lighting: Profoto Lights & Modifiers
