A film crew is made up of all the movie-making professionals outside of the Actors–often referred to as the cast–whose specific expertise and contributions result in the ideation, production, and ultimately distribution of a film.
While some sort of film crew is needed for a film production to run smoothly, the exact number can vary based on the needs of the project. A small indie production can have a scrappy film crew consisting of a couple of people wearing many hats. For a studio-backed blockbuster with a nine-figure budget, you may potentially have a thousand film crew members when counting them all the way from development to distribution. This is usually the case with movies with a strong VFX presence, as it often takes hundreds of people to complete them all.