When playing online you can use your night vision googles and still be in the third person perspective. This allows you to see much more that you normally would in first person. To do it, hold down select so that the scoreboard is displayed. While the button is depressed push UP, UP, DOWN, UP. If done correctly night vision should be on and you can still see your character. (Sometimes you have to keep pressing up and down a few times for it to work.)