Z then arrow keys, find spot you like, hit f10 Zoom saved where you want.
this is a good tip, although I am happy with where mine is by default.
but good to know that you can alter it like that.
since getting trackIR I have the up/forward hat switch set as my zoom in toggle, and i use it all the time...not always for shooting, it's also very useful for getting a clearer look at opposing (or friendly) planes when trying to assess the direction they are flying in or what maneuver they are doing.
i do use it for shooting, but not all the time. generally on crossing shots or high deflection i will
not use zoom. but sometimes i do
my squaddie SirNuke uses zoom on pretty much every shot and has great success at high speed BnZ shots with lots of deflection, but I have been unable to emulate his technique.
generally i find zoom useful when firmly saddled on an enemy, to ensure accuracy and a nice clean kill. nothing more annoying than beating someone in a fight, getting their six, and then having them get away through sloppy gunnery. zooming in helps me correct my aim if it's a bit off, or sometimes aim for specific parts
actually in case anyone cares there are some examples of how i use zoom in this video
http://www.youtube.com/watch?v=ISviFJZks_8 ... you can see i'm partly using it to get a better view of what the enemy planes are doing, and partly to help me take more effective shots