Born in New York, she was mostly educated in Europe - her father was a diplomat whose great uncle was the art historian Bernard Berenson. Berry inherited her father's gift for languages.

Her ambivalent career was partly a product of these aristocratic antecedents and connections. Through her better-known sister, the actress Marisa (Death In Venice, Cabaret and Barry Lyndon), she came to photograph a roll-call of Hollywood stars: Tuesday Weld, Ray Brock, Pilar Crespi, Candice Bergen and more. The sisters were raised as socialites who entertained, and were entertained by, both the cream and the froth of society.

One of this charmed circle, Diana Vreeland, the legendary editor-in-chief of Vogue magazine - and sometime fashion editor of Harper's Bazaar - set her up as a fashion photographer. She began to work for both magazines. Without ever straying too far outside the conventions of the medium, she enjoyed "playing" with her models - several of whom she knew anyway - in setting up a shot.

This career path brought the sisters together to create Dressing Up, for which Berry took the portraits and Marisa provided the text - and modelled some of the outfits. Her most recent publication was a working biography of the couturier, Halston.

In 1973, she married the actor Tony Perkins. She was three months pregnant, a condition that prompted her mother, the impressively titled Marquesa Gogo Berenson di Cacciapooti, to call her a "degenerate". Despite Perkins's homosexuality, Berry remained his wife, and cared for him in the last two years of his life.

During their marriage, she had carved out an alternative career path as an actor. In between cover shoots for Life magazine, she was shooting films. Particularly after 1978, when both her sons were well beyond babyhood, she played major or minor roles in such films as Remember My Name (1978); Winter Kills (1979), a political melodrama with a cast that included Perkins, John Huston and Elizabeth Taylor; Cat People (1982), a horror mystery; and in the 1980 TV series, Scruples.

Many of these roles had a sinister undertow. In Alan Rudolph's Remember My Name, for example, Perkins and Berenson co-starred as a suburban couple whose lives gradually come apart following an apparently random act of vandalism.

While Perkins summed up his personal tragedy, après Flaubert, with: "Face it gang, I am Norman Bates," Berry Berenson has been given a very different memorial. In the wake of the horror of her death, her spokeswoman Susan Patricola commented: "She was one of the loveliest, greatest people on the earth, full of life." At the time of her death, Berenson was returning home to Los Angeles after holidaying on Cape Cod. She is survived by her two sons by Anthony Perkins: Osgood, aged 27, and Elvis Perkins, aged 25.

Ronald Bergan writes: During therapy, for what he believed would "cure" his homosexuality, Anthony Perkins was asked what sort of woman attracted him. He flipped through a copy of Vogue until he pointed to a spread on Berry Berenson. Coincidentally, Berenson claimed: "When I was 12, I fell in love with Anthony Perkins in Phaedra." Ten years later, in 1972, Berry visited her screen idol at the New York townhouse he shared with the dancer Grover Dale, for Andy Warhol's magazine, Interview. "I thought she was cute and pretty but a little frantic," Perkins recalled. Soon after, they started to go out together.

In 1973, She and Tony got married. An ex-boyfriend of Perkins, photographer Chris Markos, said: "The funny thing is that Berry and I looked similar - we both had short fair hair and similar features. This was noticed by the Andy Warhol crowd, who joked that he substituted Berry for me."

However, there is no doubt that Perkins was both sexually attracted to and in love with Berenson. There was also agreement among their circle of friends that she either did not know about his sexual adventures before and after their marriage, or that she preferred not to know, or, in fact, care.

Then, in 1990, Perkins was tested positive for HIV. He decided that he wanted the knowledge kept secret even from their intimates, which heaped a tremendous burden on Berenson. When Perkins got Aids, she finally decided to tell a few of their closest friends - "to share this grief with us". On September 2 1992, Perkins died with Berenson clutching her husband's hand. "We had a very satisfying life together. It was a wonderful love affair. If anything else was happening, I certainly didn't know about it, and I don't think he intended to hurt me in any way."

 Berinthia 'Berry' Berenson, photographer and actor, born 1948; died September 11 2001