It’s a trade-off with biopics on dead rockers: You please the James Brown estate and get the music (Get On Up); or you go warts-and-all, like first-time director John Ridley in Jimi: All Is by My Side, and forego rights to “Purple Haze” and other classics. Ridley, whose script for 12 Years a Slave took home a well-deserved Oscar this year, makes a virtue of his limits, catching Hendrix (Outkast‘s André Benjamin) in the fascinating act of inventing himself in New York and London in 1966-67 and giving his film the loose, risky feel of a Hendrix drug haze. The movie has a tossed-off, caught-on-the-fly exuberance that works like a charm. Among the women in Jimi’s life at the time, Imogen Poots makes a vivid impression as Linda Keith, the 20-year-girlfriend of Keith Richards and a force of nature in furthering Jimi’s career. It’s Linda who gets him to change his look (that Afro), try LSD, and sing as well as play the hell out of the Stratocaster she buys him. Hayley Atwell also shines as Kathy Etchingham, Jimi’s Yoko Ono and a firebrand who brings out the feeling and scary ferocity in Jimi. Kudos too for Andrew Buckley as Chas Chandler, the manager who takes Jimi on and sees him off to Montery Pop, the concert event that would jump-start his career in America. But even in electrifying scenes like Jimi opening his show at London’s Saville Theater by putting his unique spin on the title track of the just-released ‘”Sgt. Pepper’s Lonely Hearts Club Band” right in front of Paul and George, there’s no doubt that Benjamin is the film’s magnetic core. Benjamin’s silky-voiced, dangerously volatile turn as Jimi is a star-spangled triumph.