The prime exemplars of modern documentary, centered on filmmakers’ close involvement with their subjects, are fundamentally transactional. They depend on the willingness of participants to let the filmmakers follow them in public and in private, and thus on what the participants think is in it for them to be filmed so intimately. The spate of documentaries that put nonfiction films on the artistic map in the nineteen-sixties (such as “ Primary ,” “ Salesman ,” and “ Don’t Look Back ”) are all essentially works of coöperation, even collaboration, but also of willing subjection to the filmmakers’ authority and authorship.

Those films—the styles that they set, the methods that they advance, the conflicts that they imply—involve trust, which is the prime fault line of conflict in Robert Kolodny’s first feature, “The Featherweight,” a faux documentary with nothing “mock” about it. Kolodny, working with a script by Steve Loff, tells the story of the real-life former champion boxer Willie Pep’s effort, starting in 1964, to make a comeback at the age of forty-two. That comeback is both the subject of the film and its premise: as part of his effort, Willie (James Madio) has recruited a pair of documentarians to follow him around, in order to create a portrait of him that he can use for self-promotion.

“The Featherweight” purports to be the resulting film. Kolodny’s feature doesn’t merely depict the era but masquerades as a product of the era.