Action or objects outside the frame — audience hears or infers them, doesn't see them. Creates tension and engages imagination more than what's shown.
What happens outside the frame often has a stronger impact than what you show. Off-screen isn't simply invisible—it's an active dramaturgical decision that forces the viewer to supplement, fear, and anticipate on their own. You guide their attention through sound, the reactions of actors within the frame, or subtle visual cues. The viewer's brain works harder because it has to fill the gap—and that makes the scene more memorable.
In practice, off-screen works through several channels. Sound is the most important tool: you hear footsteps approaching but don't see the person yet. A door slams, a voice calls out, glass shatters—all recorded outside the frame and later positioned in the mix. The viewer automatically projects what they don't see, often worse or more intense than you would have staged it. This is the power of suggestion. You can also use the gazes and reactions of the actors: someone looks in horror at something beside the camera—you don't show what it is, but their fear is conveyed. The image then forms in the viewer's mind through editing and sound design.
Practically on set: If you want to build suspense, often keep the camera on the person who hears or senses a threat—not on the threat itself. You can instruct the actor to look and react in the direction of the off-screen object. This is more genuine and economical than showing everything. Off-screen works similarly in action scenes—not every shot needs to be in frame; sometimes the sound and reaction are enough. It also saves budget: you don't need an elaborate set for everything that happens.
Off-screen works particularly well in horror and thrillers, but also in drama. Think of scenes where someone is waiting for a conversation or listening for danger—the tension arises not from visibility, but from not knowing. The viewer fills the gap, and their imagination is usually more intense than your best staging. You just need to set the frame and let the unease build through sound and reaction.