The rule of thirds refers to dividing an image frame into thirds with imaginary lines, both horizontally and vertically, creating 9 sections. The focal point of the image should fall at the intersection of these lines or along the lines. For interviews in documentaries, the subject should be placed along one of the vertical lines with their face falling in the upper left or right section. While the interviewer stands off camera facing the subject, they will take up around two thirds of the frame similar to over-the-shoulder shots.