Of course the p4 is not for a canon D5. There are interesting cases though, when the default fov is not sufficient, there are plenty of examples for adding a 360 camera (around 200g) or lightweightHanging a heavy camera that you can't see through and can't control is pretty pointless.
Particularly when it's going to eat your flight time and the Phantom's performance.
What did you stitch this with? Reason I ask is that the horizon is pretty perfect. Very little - if any- distortion.When the default FoV is not enough, it's time to learn to shoot panoramas.
This one covers 180°