I have a Nikon D90, and I usually prefer to shoot in Aperture priority mode. However, recently when I go into Aperture mode, I can adjust the aperture, but I can't adjust the exposure, and the hash display that shows if it is over- or under-exposed or spot on, is no longer in the display. I'm hoping there is a simple fix. Maybe I accidentally changed a setting that I didn't realize that took it off? Anyone know if this is fixable and if so how?