If I want to write in the film credits that I am an author of the film, which formulation is more correct:
film by Name Surname
or
fim of Name Surname
If I want to write in the film credits that I am an author of the film, which formulation is more correct:
film by Name Surname
or
fim of Name Surname
There are several possibilities, e.g., A film by Maxim Velichkin, or Filmed/Made/Produced/Directed by Maxim Velichkin (the slashes indicate alternatives). Anyway, I guess that you probably wanted the former, A film by Maxim Velichkin, and I'd recommend keeping the article A in front of film.
As a movie buff, I think it's always by in the credits, at least as far as I can recall. The preposition of is also possible in conversations, but it must be very rare in the credits rolled at the beginning or the end of movies.
Here are some examples of the results returned by Google when I searched for images of "a film by":
If you try "a film of", you will get virtually nothing related to movie credits.
The preposition by used after a passive verb shows that someone has done something, and that something is done by him (first and middle name, whatsoever). So if he shot a film, the film is made by him - name, surname, or whatever - the film is by that person.