So in older version of DJI Go app next to the AE lock symbol there was a box that was autofocus and if you clicked on it, it changed to exposure and then you can tap on the screen to do those. I noticed in DJI Go 4, I don't have that box next to the AE lock and I wonder where it went. I found I could set a C button to center meter exposure, but would still like to click to expose on certain shots.