'Son of Saul' director László Nemes: 'The unimaginable must be imagined'

László Nemes' gruelling Holocaust drama "Son of Saul" has been building awards momentum ever since blowing audiences away at its Cannes Film Festival premiere in May. The director speaks to Eve Jackson about the challenges of making a feature about the Sonderkommando. Also on the show, the movie "The Walk" that's making audiences physically ill, plus the little French film "William the Conqueror" with the big ambitions.