The Iron Claw, written and directed by Sean Durkin, is about, among other things, the perseverance of brotherhood, despite or in spite of a father's smothering grasp. With sparkling, dust-mote-friendly cinematography by Mátyás Erdély, Durkin composes a film that's as intimately observed as a shaggy character study from the 70s, and as sharp as a tungsten nanoneedle.