If a memoir inevitably looks to the past, it's most stimulating to witness Kirsten Johnson's testament for the future, Cameraperson. It's less a highlights reel than a lowlights reel, a compilation of all we've missed and not a condemnation but an explanation of how we missed it. Her memories shaped our own with indirect force - now she presents the details of that process with direct force, and reframes our interpretations of the past with simple, straightforward honesty. Cameraperson is thus more persuasive and more enlightening as a statement in its entirety; individual scenes oscillate between plain beauty and plain ugliness, dramatic integrity and dramatic stagnancy - necessary differences given the range of sources, though the film is thereby rendered close to an anthology feature in its effect. What Johnson, whose voice is frequently heard on the consistently diegetic sound mix, proves with every image, however, is the vitality of the cinematographer in documentary filmmaking, and the extent of the viewer's dismissal of their role. Indeed, that dismissal is argued here as being greater the less the artist fights against it, and so it's fulfilling indeed to examine the nature of that role and its cruciality in the production of earnest, effective documentaries. The revelatory power of Johnson's images may deplete commensurately with their level of development; she combats this with sensitive cross-cutting whose impact is possibly a little too blunt. But these are her memoirs, and she may do as she pleases with them. And what she does is noble, skillful and resolutely valuable.