I have never heard the word "filmophile" used. "Cinephile" is more academic than "movie buff" or "film buff" cinefile = a person who is very interested in and enthusiastic about cinema as an art form, and knows a lot about films a movie buff is just a person who knows a lot about film and/or likes to go to films, but is not necessarily interested in film as an academic subject or an art form film see: https://dictionary.cambridge.org/dictionary/english/cinephile?q=Cinephile

Thank you, Matthew.

but movie buff is by far the most commonly used in my opinion

no I wouldn't say so