Beware of the auto focus setting "C" for continuous.
If one reads the manual it sounds like a good setting for us aviator fans. Was intended to "continuously" focus on moving objects towards and away from the camera user. Sounds good when your subject is near overhead, right?
Every shot taken while coming at you and going away is not in focus. But when your subject is right in front of you and one can "pan" only then will be sharp.
Unfortunately for me, while whipping out my camera at the airport I've inadvertently moved the switch to "C". Then at some point it was moved again to "S".
Single servo, "S" is where it needs to be at all times. I have hundreds of ruined shots to prove this. After examining lots of shooting data this flaw was found.
Nikon should have put a damn lock on this, it moves too easily!