A presentation, given as a lecture to technology students and as a seminar talk to Swedish filmmakers and academics, on how new participatory-design technologies open up opportunities for a new approach to documentary, and especially ethnographic, filmmaking. My project, Tales from Two Cities: Ten years in the megaslums of Krarachi and Mexico City, was presented as a potential case study, in which inhabitants of two of the world's largest slums would be empowered to make to their own stories through film.