While flying today, the app told me that I needed to calibrate the camera. I entered the camera calibration menu from the main camera settings menu, and chose a suitable hi-contrast subject more than 50 M away (as I recall). I then selected a focus point by tapping the screen and pressed "OK." After that, the app just greyed out everything except "cancel", so after 15 or so seconds, I cancelled. Did the calibration finish, or is there some indication that it has succeeded? The camera was then in manual focus (which is practically useless). Has anyone had a successful calibration of the main camera, and how did you know?