I should have written "basic photography knowledge". In manual mode, there is no reason to use EV compensation dial as the exposure "compensation" is achieved using the ISO or the shutter speed setting.
Photography itself is somewhat "basic" (using a high end DSLR or the P3 doesn't change anything to this fact) : the correct amount of light has to reach the sensor to have your subject exposed correctly. And to do this, you have 3 controls on DSLR (2 on the Phantom) : aperture (fixed f/2,8 on the P3), shutter speed and sensitivity (ISO).
Keeping in mind low shutter speeds will lead to blurred images and high ISO will lead to noisy images you have to choose to correct mix between the 2.
EV compensation is a way to change exposure decided by the electronics auto mode... which is, most of time incorrect if you have ground and sky on the same scene.