An ambitious, demanding documentary that weaves together philosophy, neuroscience, ethics and observations on the very nature of film-making, All Light, Everywhere is bracingly challenging stuff. Taking police body-camera technology as a jumping-off point, the film explores the act of seeing, biases in perception, the nature of surveillance and the fallibility in the way we process information. It springs restlessly between ideas and, while it doesn’t quite cohere into a neat central thesis, the film did leave me with both the means and the inclination to do some further thinking on the subject.