I was experiencing jittery movement/stuttering camera movement even though my frame per second was a constant 60, and had a hard time finding a solution on the internet. Now I have fixed this issue, I thought it would be a good idea to post my simple solution here.
My jittery/stuttering camera movement only occurred with the mouse, not with the Xbox 360 Controller, and it was the worst when turning the camera around facing the sea in the LIGHTHOUSE map.
My simple fix is: disable Vsync in the game, and in D3DOverrider (if you use it). Now I have butter smooth gameplay with an average fps at 80.
Hope this may help someone!