...that way the camera doesn't move with the shutter open as you release the button.
Another thing you might want to try is change the EV value. When I shoot on white, I usually set the EV at +1.
Experiment and see what happens when you shoot pics at -1, 0, and +1 and +2 on you camera. You should end up with something like this:
Also play with the white balance settings. You should end up with something like this:
This is what a photo shot on white should look like:
Alternately, when shooting on black backgrounds, go to EV=-1:
I hope this helps,