Wisdom has it, summer is for action thrillers, rom-coms, and other popcorn movies, but this season is particularly rich. Last week’s opening night for the BAM CinemaFest set the tone of excellence with Richard Linklater’s epic masterpiece Boyhood. With stellar performances by Patricia Arquette and Ethan Hawke as divorced parents, the film, shot in a dozen years, follows the growth and maturation of their two kids, played by Ellar Coltrane and the director’s daughter Lorelei Linklater. But this is “boyhood,” and therefore Ellar Coltrane’s film. A family saga unfolding in 2 hours and 45 minutes, the film is so deeply satisfying, the way a great novel takes you into a fully realized world. Perhaps it is a bit early to predict the award season picks, but this film has the vision, scope, Oscar dimension. At the BAM after party, directors Julie Taymor, who just completed filming her extraordinary Midsummer Night’s Dream, Bennett Miller, just back from the success of Foxcatcher in Cannes, and Oren Moverman, now editing his new film in which Richard Gere plays a homeless man, all agreed about Linklater’s achievement.