Having majority of my experience with Nikon's flashes, I know Nikon's lower end models cannot do FP and you are limited to Flash X-sync rate listed for your camera. With some of the better flashes like SB600 and above, you can do FP. I remember that Canon's 430EX2 is able to do FP, but I can't figure out from reading any reviews if 320EX is capable of it?

