[Shower thought] Why can't we have buttons for moving focus back and forth in live view?

This seems like a very basic thing that somehow never get put into (most) cameras. I just want a button to move focus forward, and another button for backward, so that while recording video, I can do focus pull without investing in a mechanical puller plus ring for the lens, and a lot less hassle when handholding the rig. via /r/photography http://ift.tt/2vXF2ea