I've gotten excellent results with the D200 and three SB-800s. I put one on the camera set in commander mode and the other two bounced into white umbrellas. I printed out detailed instructions on how to set the commander and slaves so I don't make any mistakes on location.

Have you read Dave Black's SB-800 page?

Not knowing exactly how you are setting everything, it's difficult to try and figure out what's wrong, other than the flash is not pointed directly at the subject or bounced into an umbrella positioned properly.

Larry,

I am using a sb-6 and 800 pointed directly at the subject. A pretty basic setup. I can use Commander/ Manual Mode and set the flash output but that is counter to AA and TTL. Any suggestions are appreciated.

Hi all,
While D70's built-in flash works as a pre-flash in the commander mode, it does not contribute to the brightness or exposure of the shot. The light/brightness in this case, will have to come from the external/wireless flash. So it could really result in underexposed shots depending on the external flash position and the number of flash being use.
This is peculiar to D70 or D70s, D80 and D200 do not have such problems as their built-in do contribute to the brightness of the shots.