Tierney Gearon's art is all in the family

It's as famous a sentence as there is: "Happy families are all alike; every unhappy family is unhappy in its own way." Yet if Anna Karenina had been an artist, Tolstoy would have had to add another clause: "But let's talk about me."

Part of the fascination of "Tierney Gearon: The Mother Project," which runs at the Museum of Fine Arts as part of its "Art on Film" series, is that the documentary is so firmly planted at the intersection of - maybe that should be collision between - artistic self-involvement and family.

An American, Gearon is a photographer who first drew attention in 2001 when some of her pictures were included in an exhibition at the Saatchi Gallery, in London. Several showed her two young children in various stages of undress. Uproar ensued. In the documentary we see a TV talking head describe the pictures accurately, if inelegantly, as "not graphic, but just a bit pervy."

Trained as a dancer and later a model, Gearon found herself launched on a high-profile photography career. She'd also discovered her abiding subject: family. We see her obsessively shooting her children (there are now three) and her mother. There are also a few glimpses of her father, but he's at best peripheral. The subtitle announces the documentary's thrust: Gearon's being a mother and the daughter of one.

Early in the film, Gearon confides that her mother is manic-depressive and schizophrenic. The older woman is clearly a handful. "Are you going to pay me for my time, Tierney?" she asks as she poses. Still, the daughter's description sounds like the sort of exaggerated complaint most adult children will make about a difficult parent. By the time the Mom confides that she's the secret daughter of the Duke and Duchess of Windsor, we see what Gearon means.

By then, we've also seen that Gearon is herself a bit unhinged. She doesn't rail at her children, as her mother does at her. But she shows no compunction about clicking away when her son starts wailing at a picnic after being bashed by his sister - Weegee should have been so thick-skinned - and her consternation when she sees in print the results of her having done nude handstands while posing with her (clothed) children for another photographer would be hilarious if it didn't indicate such astounding obliviousness.

Some of Tierney Gearon's photos are very good, especially her portraits of her mother (who's almost as striking in appearance as she is in behavior). But what the documentary makes plain is that photography isn't really Gearon's calling. It's performance art - more specifically, multi-generational performance art. "When I do things, I do things full force," she declares. There's no doubt about that, nor about her mother's willingness to participate (her occasional recalcitrance notwithstanding). It's the children one wonders about - and fears for.

Mark Feeney can be reached at mfeeney@globe.com.