"Iron Maiden: Live After Death." Sony. $29.95. Iron Maiden is one of the best heavy-metal bands going and this 90-minute concert film (drawn from a four-night engagement a year ago at Long Beach Arena) gets dive-bomber camera work and dynamic editing worthy of a "Star Wars" sequel. Nevertheless, it's largely a bore. The English quintet performs every number with the same bravura poses. Maiden's above-average musicianship (its two guitarists transcend metal barriers for progressive-rock intricacy) is a feature of interest, but you can get that on the less-expensive live album of the same name.