A dispute about who took a photograph, or who is the owner of copyright in a photograph, may need to be resolved by a court if the parties cannot agree. A court considers all the relevant evidence presented to it. The most important evidence is usually the oral evidence of the parties and of relevant witnesses. Other evidence may include a copy of an agreement between a photographer and his or her client, negatives and proof sheets. A copyright notice on the photograph may be relevant to the question of ownership, but it is not conclusive.
Such cases are rare; someone else claiming to own copyright without any basis, generally runs large financial risks in bringing such a case.