Your heart goes out to Eric Clapton during this documentary, which examines the bone-deep sadness that has been as much a part of much of his life as the guitar. Unfortunately, unless you are a diehard Clapton fan, your patience may give out around the same time. Lacking the crackling nastiness of Beware of Mr Baker, about Clapton’s Cream bandmate Ginger Baker, or the window into prickly brilliance offered by What Happened, Miss Simone?, this Clapton-approved portrait feels a little plodding and weirdly grudging with its insights.