A distinction must be drawn between criticism and reviewing. Most people who call themselves film critics and publish commentary on films in periodicals are actually film reviewers. A film criticism is actually more closely aligned with PhiloSophy
than it is commentary. The film critic tries to come to understand why film works, how it works, and what effects it has on people.
Some of the names you must know in exploring the world of film criticism include:
Of course there are many more, but these will put you on the right track.