Hi, I dun know about raynox on a 50mm, but I am using a Vitacon "macro+wide angle" combo on a D40 kit lens and here is a sample of a macro shot with only the macro lens:
i am using manual focus. when you use raynox dcr-250, you need to place your camera directly/flat in front of your object to have a good focus. try not to slant your camera.