The Oscar-nominated documentary short “Poster Girl’’ is Newton native Sara Nesson’s first film, but it was only a matter of time. After all, she’s proud to say, it was beneath her father’s editing table that she learned to crawl. Robert Nesson of Somerville, an independent producer/director whose films focus on the environment, human rights, and educational projects (he’s also an instructor at Emerson College), taught his daughter not just the nuts and bolts of filmmaking but how it can raise awareness and effect social change.
