I'm very heavily involved in the editorial post-production process, and the camera - it's just such a big part of my storytelling language. I like creating the tension; I like creating the emotion through the movement of my camera, or the lack of movement through my camera, depending on what fits the scene best.
When you create those characters that people love and care about and put them in a dark hallway, already the audience is on edge, and they feel empathy for that character. Then it's up to me to decide what jumps out in that hallway. So I think laying that foundation of strong characters and strong story is the most important thing in a horror film.
I remembered a long time ago when 'A League of Their Own' came out, and they had the opening sequence with an older Geena Davis. We all just thought it was amazing, but you find out it actually wasn't Geena Davis; it wasn't makeup. It was basically finding an actress that looked like her, and then Geena just dubbed her voice.