"Photography will always be my first love," Helmut told her, "but you will be my second." Even so, t

June is now in her early 80s, though she could pass for 20 years younger. An important photographer in her own right, she was also Helmut's editor, confidante and curator, and the subject of some of his best portraits. He may have taken centre stage but she was central to his work - and still is. When the "king of kink" was attacked for his sexualised portraits of women, June sprang to his defence. "Well," Helmut once said, "she's Australian, you know." Her line on his work is much the same as his: he adored powerful women - women who were attractive but above all tough, like his wife. Why, she argues, would he spend a lifetime photographing people he loathed?

June lives in Monte Carlo, but is in Berlin to open the latest show at the Helmut Newton Foundation. There are about 1,000 of Helmut's pictures in this museum, and about 400 of hers. "There's too much to put on the walls at once, especially in Helmut's case," she says. So the foundation has been housing a series of shows, the latest of which is a display of Helmut's work called Yellow Press, inspired by the paparazzi. "He was always interested in the National Enquirer - anything to do with sensation. It was the last exhibition he worked on."

Helmut and June were busy planning the opening of the foundation when he died in a car crash on Sunset Boulevard in Los Angeles. "The moving force behind the Berlin project was my wife," Helmut had said, and after his death, she made sure it opened bang on time. It is housed in a former Prussian officers' club that stands, poignantly, right beside the train station from which Helmut left Berlin to escape the Nazis in 1938.

If it hadn't been for Hitler, the couple would never have met. Helmut Neustädter was born in Berlin in 1920, the son of a wealthy Jewish industrialist. He fled Germany when he was 18 and ended up in Singapore, where he worked as a high-class gigolo before being shipped off to Australia and interned as an enemy alien. After a spell in the Australian army, he anglicised his surname and resumed his photographic career. He opened a studio in Melbourne, where he met a young Australian actress called June Browne.

"I looked at the pictures on the wall and I fell in love with them," recalls June of her first visit to Helmut's studio, where she hoped to make some extra money as a model. "From that moment, I went to work. I've never stopped since. That's why I'm here in Berlin." In his autobiography, Helmut wrote that "it was a totally different affair from any I'd had with any other girl. All the other girls were really only about fucking. With her there was another dimension."

"Photography will always be my first love," Helmut told her, "but you will be my second." Even so, they were married within a year.

In 1956 Helmut came to London to work for British Vogue. June went with him, even though her acting career was flourishing in Australia. She found work with the BBC but Helmut had a rotten time. In the deferential era of Norman Parkinson, Helmut's noirish shots were anathema; even shooting a woman leaning against a lamppost was regarded as too risqué. The couple moved to Paris, where Helmut's career began to take off. June, however, found the language barrier insurmountable. Instead she taught herself to paint, and in 1970, when Helmut was ill with flu, she shot an assignment for him, an ad for Gitanes cigarettes. It was the start of her own photographic career, under the pseudonym of Alice Springs (chosen blindfold, with a pin and a map of Australia). She shot clothes for Vogue, Elle, Marie Claire and Vanity Fair, as well as advertisements, and despite working as Helmut's art director - advising, editing, organising - soon established her own style.

June's photographs have an intimacy that Helmut's lack, a difference which is obvious when you look at their parallel portraits of famous people side by side. "We never photographed the same subject together," she says. "We had a very different approach." This is evident in their shots of Gianni Versace and Charlotte Rampling. Helmut's Versace is naked yet confident. Hers is clothed yet more exposed. Helmut's Rampling is an actress in a movie. Hers is the woman behind the mask. "A woman photographer can never, ever get what a man can out of a woman," she says. "I used all the acting skills I had to make people relax, dwell within themselves and just look at me."

June and Helmut's portraits of each other, and of some of the many people who sat for them, are collected in a book called Us and Them, which formed the basis of the Helmut Newton Foundation's opening show, and reveals the wit and warmth of their 55-year marriage. The most significant addition in the exhibition was a photo of June embracing Helmut on his death bed. "I can see the truth and simplicity in the portraits of Alice Springs," Helmut wrote in the introduction to the book. "As for myself, I recognise the manipulation and editorialising in my photographs."

Some of June's most truthful photographs have been gathered together in June's Dark Room at the foundation: there are portraits of William Burroughs, Christopher Isherwood, Roy Lichtenstein, Robert Mapplethorpe and Christopher Reeve before he broke his neck, looking lithe and self-assured. "It's a Dark Room because they're all dead," says June. "I wanted to call it La Chambre de la Mort but they said that was a little too morbid."

Now she is planning a room called June's Living Room, full of people who are alive. "I can never photograph anybody without the regard in the eyes," she says, trying to describe the connection she makes with her sitters. "You will never see a regard in anybody's eyes in Helmut's pictures. You will only see the eyes. He wasn't interested in people. 'I'm not interested in soul,' he said. But I was, and I tried to steal them. And in many cases I did." Her rueful, sad-eyed portrait of Graham Greene was "the only picture of mine that Helmut was jealous of", she recalls.

June also shot the definitive film of Helmut at work. Like her photographic career, it came about by accident. She wanted to give Helmut a video camera for Christmas, but he told her he was "a still photographer, not a movie-maker", and so she bought it for herself. The result was an enthralling documentary, Helmut by June. As with her still photography, intimacy and truthfulness are its greatest strengths. "I know him so well, and I know his work so well."

I ask her about her husband's death. "Helmut was about to shoot a big job in America," she recalls. "The models had flown out from New York." Helmut died on Friday. The shoot was set for Monday. "The production manager said, 'What will we do?' I said, 'We'll have lunch.' So we went to lunch at his favourite diner, Mel's, and then they said, 'Do we send all the models back? Do we send the clients home? What do we do?' I said, 'No. I'll do the job. I've got the assistant. I've got the studio booked. I've got everybody. I'll do it.' That's how I got over it.' And that's how she still gets over it. "Go to work. That's it. Just work."

We stop off at the Friedenau cemetery in the leafy suburb of Schöneberg, where Helmut was buried two years ago - a few feet away from Marlene Dietrich, a few minutes' walk from the apartment block where he was born. There was no priest and no religious ritual; there were bells instead of an organ. June sang a song from Brecht's Threepenny Opera. Chancellor Schröder was there. For the Germans, it was an important homecoming. Not so many Jews have been willing to return to Berlin.

There are still flowers on the grave, and June and her friends have brought plenty more. There is a photograph of Helmut on the gravestone, wearing a Mona Lisa smile. It's a simple head-and-shoulders shot, as straightforward as a passport photograph, but there is something so tender and intimate about it that it comes as no surprise to find that it was taken by June.

· The Helmut Newton Foundation is open from Tuesday to Sunday in Berlin. Details: 00 49 30 3186 4856 or www.helmut-newton-stiftung.de