In my earlier posts, I've talked about ways that you can adjust the brightness of your pictures. Even using Exposure Lock or Exposure Compensation, your pictures may turn out too light or too dark. Here are some possible causes and what you can do to prevent exposure problems in the future.
One reason your photos may not be properly exposed is the new controls you've just been using. If you did not reset the Exposure Compensation marker back to zero after your last picture, your picture could be too light or too dark because the camera is still following your instructions! Check to be sure that exposure compensation is set to zero.