Narration

So what is a narrator? 
Narrators can be used within every different sort of story. Whether that is a story, a television program, piece of theatre or a film. Narrators are the people that effectively tell the story to the audience. If the narrator is a character within the film/play/program he or she is sometimes referred  to as the viewpoint character. 
When you talk about the narratological inventory applied to film or cinema it is important to realise that lots of other techniques are used as well to convey the story. Its often thought that there is no narrative with out a narrator. This isnt all true in my opinion, other devices must be taken into account of course. Often the absence of a narrator can be compensated greatly by visual narrative- this relates to elements such as camera, sound and editing. Also another imperative element is mise-en-scene.
Without these few key conventions a film would be far less effective. Adding a narrator into the mix normally means that the audience can really delve deeper into the film world, making the film far more accessible. 
Its often the case that the narrator will reveal information, this is where dramatic irony could take place or perhaps reveal feelings and emotions of a certain character. Both of these things adds to the audience either empathising or sympathising with characters. Once again drawing them far closer into the film. 
Sometimes its the case that narrators aren't there throughout the entirety of films, often they are there at the beginning to set the scene and sometimes appear at the end of close the film.