Any notion that Mark Wexler's documentary ''Tell Them Who You Are" will be an unquestioning love letter to his cinematographer father Haskell Wexler is brutally dispelled 30 seconds in, when the director asks his subject to describe the camera equipment room in which they're standing. ''If you don't know where the [expletive] you are, just look around," barks the older man.
Yes, it's going to be one of those ones. Whereas working out anger toward dad once required 30 years on the couch, enterprising filmmakers have lately created a mini-genre of oedipal documentaries that probe and accuse and puzzle over the private legacies of public men. Nathaniel Kahn's ''My Architect" (2003), Lucia Small's ''My Father the Genius" (2002), and Jenny Abel's rather more fond ''Abel Raises Cain" (2005) are all attempts to frame larger-than-life patriarchs in the long, caustic view of their adult children. To one degree or another, these movies are attempts to be heard, if not by fathers who've never been very good at listening then by an audience of strangers. They are Exhibit A.
''Tell Them Who You Are" is so overtly a case for the prosecution that the director occasionally cuts to gloomy childhood photographs of himself after dad has landed a particularly lacerating psychic blow. And yet the film holds steady and rarely asks for pity. If it has a flaw, it's that the younger Wexler doesn't seem sure what he's asking for: love, revenge, forgiveness, proof? He just keeps filming, hoping for answers.
Haskell Wexler is famous within the film industry and virtually unknown outside of it. He was cinematographer on some of the most important films of the 1970s -- ''One Flew Over the Cuckoo's Nest," ''Bound for Glory," ''Coming Home" -- and, while working his way up in the '60s, directed and shot one of the great inquisitions into media, responsibility, and revolution, 1968's ''Medium Cool." He's also one of Hollywood's last committed leftists, unflinching in his articulate outrage at the system.
And he was, clearly, a difficult man to grow up around, especially since he seems to have decided early on that his son was a source of embarrassment rather than pride. Mark Wexler doesn't dig up old evidence, and he doesn't have to, not when his father is continually faulting his son's politics (vaguely right of center), his motives, and his filmmaking techniques. ''[Expletive] the sun setting, this isn't a [expletive] beer commercial," is about as nice as the old man gets. When someone comments on the presence of Mark's camera at Haskell's 80th birthday party, the father snorts, ''The weak part is who's behind it."
In Haskell's defense, his son's motives for making ''Tell Them Who You Are" remain frustratingly opaque. He marshals film clips, but not the ones that might best showcase his father's gifts; he gives surprisingly short shrift to the landmark ''Cool" and doesn't really get to the bottom of Haskell's firing from the set of ''Cuckoo's Nest."
We do hear from a glittering lineup that includes George Lucas, Michael Douglas, Jane Fonda, Ron Howard, Paul Newman, Milos Forman, and documentarian Albert Maysles. All praise Haskell and his art; all sense that the son is after something else.
A few of them provide it, and, not surprisingly, they tend to be people with famous fathers of their own. Douglas tersely comments that Haskell ''reminded me of my dad," while Fonda clucks empathetically over Mark. ''Intimacy scares them," she reminds him.
So does mortality. Our view of Haskell mellows as the film progresses and we observe the old man's frailty and missed chances. He can no longer distinguish colors, and he's hungry for work that isn't coming. His longtime business partner and friend Conrad Hall -- who provided the growing Mark with an easygoing alternative father figure -- has terminal cancer. Filmmaker Irvin Kershner offers this no-way-out career summation: ''He should have been a director. There are a lot of 'should haves' in life, and the 'should haves' are a curse."
By the time son films father in a terribly moving reunion with his ex-wife, whom Alzheimer's has reduced to an empty husk, accommodation if not acceptance has been achieved. That seems to be enough. Throughout the film, the director has been pestering his subject to sign the necessary release forms allowing his filmed likeness to be used. In more ways than one, Mark Wexler gets the release he's seeking.
Ty Burr can be reached at firstname.lastname@example.org.