The FPV camera compensation is cool new feature that compensates the camera angle while Yaw or Roll.

This feature allow rolling around camera axis mixing automatically Roll input into Yaw+Roll motors commands.

Credits to William Thielicke:  http://shrediquette.blogspot.fr/2016/01/explanation-video-fpv-camera-tilt.html

FPV camera Tilt compensation is located in Configuration > Stabilization tab > Advanced tab