Justin Bieber mania reaches its zenith! Pessimists will liken Jon Chu’s polished and proficient all-access doc to an apocalyptic sign of the times. (An adolescent phenom gets a big-screen biography? Where’s that razor?) The converted shall preach the gospel with ear-shattering shrieks and hands raised in heart-shaped ecstasy. But is there a middle ground? Born to a teenage Mom, 17-year-old Bieber gained prominence through a series of YouTube videos that caught the attention of R&B sensation Usher and talent manager Scooter Braun. Both are among the many talking heads that testify to the megastar’s capacities, and the glowing assessments are understandable. Beneath the innocu-pop surface is a kid with a ton of musical aptitude. But as he’s now a corporate commodity it’s unlikely his abilities will be given room to develop properly. Chu does his best to humanise his subject, showing him surrounded by friends and family and wringing much drama from an on-the-road vocal-chord strain. Yet the singer’s celebrity dictates that the overall arc must be glibly inspirational. Hopefully, the machine won’t grind this one down before his prime.