A documentary film-maker and cinematographer for 25 years, Kirsten Johnson uses clips from her vast body of work to create what she describes as a “memoir”. But this fascinating collage is more than that – it’s an interrogation of the relationship between the person behind the camera and the one in front of it; it’s an insight into the struggle between impartiality and the urge to intervene (we hear Johnson’s muttered prayers as a Bosnian toddler plays with an axe; we hear her cry along with a young woman at an abortion clinic). And although we only see Johnson’s face once, briefly, it’s a detailed self-portrait of an extraordinary woman.