most video cameras i've used produced super whites, the d90 doesn't so I'm very glad if this does (superblacks are uncommon, i only know of the 5d). can you post some screenshots of your waveform or histograms perhaps? superwhites do give you a little bit of headroom, and it's nice for secondary corrections, post flares and so on. expose your whites at 100% and the camera will still register specular highlights and lightsources as brighter than white.