Hi, I'm new to photography so please bear with me. I just got a Nikon D7000 and have shot with it twice now. The first time, my photos came out normal, but today they all came out very dark, almost black. When I uploaded them to my computer I was able to adjust the brightness and could make out the photos, but they were still very dark. Both times I shot outside in daylight on a sunny day in auto mode with no flash. An older post on this forum said that I could have inadvertently changed the exposure compensation, but I checked and it is at 0 and the photos are still coming out dark. Does anyone have any ideas as to why this keeps happening? Here's a picture to show what's going on - I took this in the afternoon when it was bright and sunny.