Se7en. Camera. The constant close ups on the hand of the killer yet not being able to see his face, creates a suspicion and mystery for the audience as to who the film is about and what they are about to do.
CU- shows the sense of torture which is up close and is very uncomfortable to watch and makes the audience hide away.
CU- of mans hands makes the audience uneasy and out of their comfort zone, amplifying the horror theme.