YOU CAN manually focus if you’re shooting remotely with your EOS camera, using either Canon’s Camera Connect app for your mobile device or EOS Utility (see page 80) on your computer. If you’re using a lens that has an AF/ MF switch, you’ll need to make sure this is set to AF, even though you’ll be focusing manually!
You can operate the autofocus as normal to get you in the ballpark, then take over by tapping the on-screen arrows to manually nudge the focus in either small or large increments. You can also magnify the image covered by the focus point to for precise adjustments, as shown here in Canon’s Camera Connect app.