In the movie industry, everyone usually signs a work for hire contract that specifies who will have the rights to the completed film.
However, in a recent case the director (Alex Merkin) did not sign a contract and then tried to claim copyright afterwards. The court said that directors have no inherent copyright over film:
We answer that question in the negative on the facts of the present case, finding that the Copyright Actʹs terms, structure, and history support the conclusion that Merkinʹs contributions to the film do not themselves constitute a ʺwork of authorshipʺ amenable to copyright protection. … As a general rule, the author is the party who actually creates the work, that is, the person who translates an idea into a fixed, tangible expression entitled to copyright protection. … But a directorʹs contribution to an integrated ʺwork of authorshipʺ such as a film is not itself a ʺwork of authorshipʺ subject to its own copyright protection.