When film and stage director Sam Mendes first showed his script for “Empire of Light” to his regular collaborator, cinematographer Roger Deakins, the subject of how to shoot the personal, bittersweet story didn’t even come up, he says.Rather, it was all about whether Deakins felt something for the central characters, Hillary (Olivia Colman) and Stephen (Micheal Ward), two lost souls brought together by a once-fabulous movie palace in an English seaside town, and whether he wanted to tell their story, Mendes says.