Many films are made with film formats that are wider than video's standard 4:3 aspect ratio. Where possible shoot proper widescreen video to enhance your 'film' look.
Many cameras with a widescreen mode produce pictures of this aspect ratio by throwing away valuable pixels from a 4:3 CCD. Check your camera's pictures in widescreen mode. If they are less sharp than in standard mode, then your camera does not have true 16:9 capabilities.
You have two choices:
But you might have problems if you don't have a 16:9 viewing capability in your editing package. Reduce the height of your video by 75% and you will have a 16:9 widescreen picture within a 4:3 frame.
2. Shoot in 4:3 but frame for 16:9 so black bars can "letterbox" your frame top and bottom in post- production.