I am in a photography class, and I'm trying to do my homework... we have an assignment to shoot 2 photos in Av setting, one with low f-stop and one with high f-stop, to show difference in DoF. We are also supposed to shoot 2 photos in Tv setting, one stopping motion, and one showing motion. I have been working on this today (with some help from my kids!), and everything looks way overexposed. I had my son stand with the trees from our backyard behind him, and the trees look ok, but his face is blown out on both settings (high and low f-stop). With the Tv setting, only the one with a slow shutter speed is overexposed. Is there maybe a setting on my camera that I've changed and don't realize it? I shot some with various apertures the other day at high noon, and they were fine, and everything I'm shooting in auto today is fine. Help! TIA!