I have the opportunity to an upcoming show. On their podcast recently, the group talked about looking for a photographer to shoot their show in my city. Someone I know, got them in contact with me. This will be an unpaid gig for me. They are a relatively unknown group. I will allow them to use the images as they like as long as I can as well and would like to be credited when they do. The question is, should I make a contract ( digital or physical)?