There are a number of techniques used in films to lead audiences to feel a certain way, and in Trey Edward Shults' horror film
It Comes at Night
the director plays with aspect ratio and lenses to create a nightmarish quality to some of his scenes.
Shults, in an interview with The Verge, explains that most of the movie is shot in 2.40:1, with spherical lenses. As the movie progresses though, and his characters begin to experience nightmares or the story reaches its climax, Shults switched to 2.75:1 and anamorphic lenses or 3.0:1.
"Over a prolonged sequence, the bars are slowly closing in, getting more claustrophobic, until they're stuck in 3.0:1 for the rest of the movie," Shults says. His goal was to have these changes not be consciously noticeable to an audience, but rather to just cause an unconscious sense of feeling.
"To me, it's not cool to be like, 'Yeah, we're geniuses! We're doing aspect-ratio stuff!' That's not interesting. But if you can subconsciously affect an audience like that, that's the real power, and the real excitement behind it." To read Shults' full interview, click