How has Annie Leibovitz attained her extraordinary kind of fame? Renowned as a commercial photographer who has produced celebrated covers for “Rolling Stone,” “Vanity Fair,” and “Vogue,” she has also established herself as a museum piece, so to speak, a fixture in Britain’s National Portrait Gallery and other venues for high art. Now there is “Annie Leibovitz: A Photographer’s Life, 1990–2005” at the Brooklyn Museum.

What separates Ms. Leibovitz from the glamour and the glitz of many other commercial photographers? Her wit, for one thing. When Nicole Kidman gets the movie star treatment from Ms. Leibovitz, you can practically wrap quotation marks around the composition, as if the photographer is both paying homage to portraits of Hollywood goddesses and sending them up.

The movie star appears in a diaphanous gown swirling a cloud-like train, making it seem as though she has just descended from the heavens. But in Leibovitz’s version, the shimmering light from above is shown to be issuing from ceiling spotlights.She exposes the mechanisms of starlight, the tools of a production system. Photography — not just Hollywood — is thus disclosed as the confection that it is.

Where have I seen this argument before? In Susan Sontag’s “On Photography,” of course. Photographs are seductive, Sontag argues, because they seem to partake of actuality. They are documents. In reality, though, the authenticity of photography is problematic. So much depends, for example, on how you light a scene.We are in Plato’s cave, Sontag suggests, taking the shadows (reflections) on the wall for the real thing. Or as St. Paul said, “We see as through a glass darkly.”

Sontag is identified in Ms. Leibovitz’s exhibition as a “long-time friend.” She was much more than that. A couple for 15 years, she and Ms. Leibovitz shared living quarters, traveled frequently together (as documented in this show), and argued about art. Sontag became a kind of cantankerous muse to Ms. Leibovitz, always insisting that the photographer could do better.

Easily a quarter of the photographs in this show are of Sontag, and they are a wonder. The shots are mostly casual and extraordinarily candid. In one sequence, Sontag is nude in a bathtub, exposing one breast while hiding her mastectomy scar. Another sequence shows the agony of her chemotherapy treatments.

It is striking that none of the glamorous book jacket pictures Ms. Leibovitz took of Sontag are in this show, even though the glitzy side of Ms. Leibovitz’s work is amply represented. The soft-focus shot of Sontag that graces the paperback editions of her work issued between 2001 and 2002 is absent. Sontag sprawls across these exhibition photographs, hair mussed, clothes wrinkled. She is shown lounging in bed but also writhing on a hospital gurney. Absent from the show, however, is a stunning series of Sontag — bloated, bruised, and unrecognizable after her final bout with cancer — photographed lying on a table one day after she died. For that, readers must consult the book “A Photographer’s Life,” which contains another hundred or so photographs that are not in this exhibition.

Artists and performers — as opposed to movie stars and other public figures, such as the uniformed Colin Powell — tend to get the austere treatment in this show. The dancer Lucinda Childs, for example, is a stark study in blackand-white, without any sort of paraphernalia indicative of rank or profession. Similarly, Las Vegas showgirls are shown first in full regalia and then stripped of even makeup — another comment, surely, on the nature of art and artifice.

This show is a kind of autobiography, and like all exercises in this genre it conceals as much as it displays. Although Ms. Leibovitz claims that her photographs of her family, her glamour shots, her war reportage, and landscapes are all one — that is, part of one life — in fact the exhibition portrays a life broken into discrete pieces. Did Sontag ever interact with Ms. Leibovitz’s family? The exhibition is silent on relationships between art, family, and love. Ms. Leibovitz seems to inhabit several parallel universes.

Perhaps she understands this point, because she includes in this show a multitude of photographs tacked onto several homosote panels, bulletin board-like structures. Ms. Leibovitz’s subjects are push-pinned here in no particular order, a conglomeration out of which the exhibition ultimately was composed.

Ms. Leibovitz took special care with this aspect of the show, arriving several days before the opening to make sure the panels were just right.They are the most honest part of the show, divulging the process of selection, and once again calling into question how photography, like all art, manipulates. A video accompanying the exhibition complements these panels, presenting Ms. Leibovitz talking about her work, her family, and how she envisioned the exhibition the public can now view for itself.

In the end, that sequence of Sontag in the bathtub may be emblematic of Ms. Leibovitz’s latest effort: The viewer may come away wondering how much has been unveiled, how much concealed — and what the artist owes her audience in a show titled “A Photographer’s Life.”

crollyson@nysun.com