It's an element that comes into play so often on professional film sets, you might not even notice it all the time. But subtle touches like haze or fog in a project can do several things for a filmmaker.
Sometimes filmmakers are adding fog/haze in order to achieve a creepy aesthetic. But fog/haze will also act as an in-air diffusion, spreading your light and carrying its color all through a set. It also adds dimension to your shot, softening the background and making the foreground subject appear crisp and sharp. Overall, it can help make your shoot feel more cinematic and sexy, rather than flat and boring.
Just take a look at the movies of Steven Spielberg and Ridley Scott. Those guys love a smoky set.
Crimson Engine takes a look at some of the most common tools used to create in-air diffusion, and what you should consider with each one. Watch their video below.
