Next time you watch a favorite feature film, watch as the hero enters his or her flat. The shafts of sunlight streaming in through the windows form striking diagonals in the frame, infusing the scene with drama and (literal) atmosphere.
Waitaminnit- have they forgetten to dust for the last decade? Did they just burn a souffle? Or has a crowd of chain-smoking fiends just left?
Actually, they’ve simply run a fog machine on the set before shooting to "put some particle in the air". For some of you, picking up a $50 – $100 fog machine at a musical instrument or DJ supply store or catalog will add a nice dramatic touch to your interior shots (but mainly if you have darker walls, direct sunlight coming in through the windows or a pro light kit with a hard light).
The farther away an object is, the more fog is between it and the camera lens, meaning that distant objects are more indistinct, leading to sort of a shallower depth of field-type effect. This technique is not for everyone, but for digital filmmakers or people shooting commercials or marketing projects that need a filmlike atmosphere this qualifies as a BIG SECRET! Shhhh! Don’t tell anyone!