When I look at the cover of a movie, I usually see the directors and/or producers name in large print on the cover. I have never in my life seen the DP's name on the front. You have credit for creating, and making a film. He is not the one getting noticed, you are. I can name all of the directors of my favorite films. I don't think I can name more than one DP. If I had a director that did that to me, I would never work with him again. I probably wouldn't recommend anyone to work with him either. Why are you lighting and shooting the film anyway? Let him do his job. I said this in an older post, and I will say it again: It is your job to tell him how you want it to look, you don't tell him how to get that look, or do it for him. If you care so much about it, and want to drag in lawyers and legal people, how about you be the DP next time. You have credit for creating the film, you are the creator. What more do you want? Also, if you want to bring in legal people, or go to court, you will probably lose.