the mirror

"The camera... is a kind of two-way glass that retains a double function: it is a window that delivers the *profilmic to an absent gaze and, at the same moment, a reflective surface that reintroduces us to ourselves." Michael Renov, from "Video Confessions" in The Subject of Documentary
*the “filmic” being everything that appears in the film, and the profilmic everything that exists in reality that receives a special destination in the film (like actors, props, decors) and leaves its traces on the celluloid.