I'm looking to get a new slr and one of the things I'll be shooting A LOT of is HDR. My preference would be to get a canon 40d since it is in my price range and is a quality camera, but it only has + -3 stops. Other cameras (such as the more expensive nikon d300) have + -5 stops. Will I ever really use the extra two stops on each end or will -3 to +3 be sufficient for pro-quality hdr images?