In a movie, the camera dramatizes the process of viewing the action and bring it on screen, allowing our eyes to see only what and how the “camera narrator” shows it to us.
A film is “told”, but the story is shown by a camera narrator. Just like a narrator in literature, the camera can use two points of view that equal the first and third person. We call them objective (through the eyes of a third person observer) and subjective (through a specific first person character).
If the story is told as one character’s story or “subjectively”, the camera plays the role of the first person observer, showing only scenes in which the main character participates. But in most movies, the camera assumes a more omniscient point of view. It is free to follow all the characters.
The real finesse begins when the camera is assigned not only a role - observer, omniscient narrator - but is also assigned an attitude (curious, amused, anticipating, foreshadowing, etc.) And a character of its own (lyrical, critical, cynical, voyeuristic, etc.). As in literature, such a role and character needs to be introduced from the start and must be kept consistent throughout the whole picture to avoid a break of stylistic unity.