Jim Marshall had an all-access pass with some of the 20th century’s greatest musicians. He was the photographer when Johnny Cash flicked off the camera at San Quentin State Prison. He was backstage with Jimi Hendrix and Janis Joplin. He toured with the Rolling Stones and photographed the Beatles’ final paid concert. “He was one of the pioneers of music photography,” said Amelia Davis, Marshall’s longtime assistant. “People have called him pretty much the godfather of rock ‘n’ roll photography.”