I'm looking for a small flash primarily for close subjects, so I don't need anything super powerful. The fact that the SB400 is pocketable is even better. I know I won't have iTTL or any fancy stuff when used with the D1X, but that's fine. My question is really whether or not the SB400 will function correctly at all on a D1X? Same question applies for SB600/800 as I'm looking to re-purchase one of them in the near future too.