My D7000 is consistently underexposing to -7EV when in manual mode. If I shoot in auto, the exposure is perfect. When in manual, the exposure meters in both the viewfinder, and menu screen show correct exposure...however, after downloading they're underexposed by -7EV. I've re-set the camera to factory defaults...same result. Any thoughts, or do I have a faulty camera (it's still under warranty)? Thanks..