Cast members from the film Sex, Lies and Videotape. Soderbergh shrugs at this, as he has in every interview he has given since Damon spilt the beans. ''I can feel it when I need to slough off one skin and grow another,'' he says. ''It's a combination of wanting a change personally and of feeling like I've hit a wall in my development that I don't know how to break through.'' There is no underplaying Soderbergh's significance within American film culture. The fact that he made Sex, Lies and Videotape for about $US1 million was held up as a beacon of hope at a time when it seemed the only viable films were blockbusters. He became the model for a generation of American filmmakers who grew up with the American New Wave, went to film school, read real books and had clear ideas of what kinds of film they wanted to make. He was lucky, he says now; he came along at the right time. ''People wanted to feel that something was made by hand again, you know, a sort of artisanal quality. They were ready for that. And there was a wave of film-makers who were ready to do that.'' Not everything those indie kids have done has been great; by no means has everything Soderbergh done been great - or even good. But behind it all, behind the congested plots and overwrought characters of the early art-house flops - the meticulous thriller Out of Sight that rescued him from obscurity; the weirdness of Schizopolis, in which his crazed suburbanites use nonsense words instead of speaking dialogue; the contemplative sci-fi remake Solaris; the experimental work with non-actors; his vast two-part epic, Che; and, of course, the massively successful Oceans series - there is always the sense of a questing, mercurial intelligence.

At the same time, Soderbergh had at least two things studio heads admire: a pride in working to a budget and a rare ability to bring the best out of actors. Jennifer Lopez gave her only good performance in Out of Sight; he guided Julia Roberts to an Oscar for Erin Brockovich; even George Clooney's winning insouciance has never fizzed to better effect than in the Oceans films. But now the time has come: Soderbergh turned 50 in January. Side Effects, his last thriller, is now playing. Later, in 2013, he will complete a film he has made for cable network HBO, Behind the Candelabra, a biopic of flamboyant pianist Liberace with Michael Douglas in the lead. That's it. From now on he will have a lot of time: time to finish reading a book and time to put it down and pick up another one, he says with a faint note of panic. Actually, maybe there won't be that much time. He might do some directing for television and his immediate plans include directing a play by his regular scriptwriter, Scott Burns, that is a reflection on the Columbine High School massacre - a classic Soderberghian subject - but his chief plan is to become a painter. He has been drawing since childhood and is already making work. He alternates between abstracts and portraits, he told a journalist who visited his cluttered studio in New York. ''I'm not really interested in landscapes or still life. I'm more attracted to faces. In fact, whenever I think of a film I'm about to make, I see a face with a certain expression on it.''

When can we expect an exhibition? I ask, half-kidding. ''I don't know,'' he says, seriously. ''It's got to be up to a certain standard. I'm just at the beginning of it, really. That's exciting and scary.'' Everyone asks the same question, he says: why now? It is because he is frustrated with movies, because he can find no new ways to tell a story. There must be a new film grammar out there, he says, but he can't imagine what it is. ''I'm going to compare myself to Picasso - again,'' he says. ''One of the things I watch for inspiration is the Henri-Georges Clouzot film The Mystery of Picasso [1956], where you see him destroying and rebuilding an image over and over again. It's unbelievable. I'm talking about that kind of transformation: that if I can't figure out a way to go from here to somewhere I haven't even seen, then I can't go to work again because I'll just be running in place. I just can't do it.'' The curious thing is that nobody watching Side Effects would guess its director was hankering for a time when revolutionary films were released in mainstream cinemas. Hiroshima Mon Amour (1959), for example - ''nobody, literally, had ever put together a film like that'' - or Ingmar Bergman's Persona (1966). ''You watch that movie now, that movie is still shocking. And that was 45 years ago,'' he says. ''So OK, where's the next leap? Where is that? I'm not talking about stuff like, 'Wow, I've never seen a decapitation done that realistically'. I'm talking about stuff that shows you a life experience that alters you when you get out the other end of it. That the humanity of it is so overwhelming that you can't un-see it or un-experience it.''

Side Effects does not set out to do any of these things. Since finishing the epic Che (2008), which he described at the time as ''a bitch'' to make, Soderbergh has kept the output high, budgets modest and tone mostly light in a succession of thrillers (The Informant!, Haywire, Contagion), a brief, experimental drama about a call girl (The Girlfriend Experience) and a surprisingly successful rom-com set in the exotically bonkers world of male stripping (Magic Mike). Side Effects is another thriller in classic style. Channing Tatum plays an insider trader who emerges from prison to find that his wife, played by Rooney Mara, is seemingly plagued by depression. He finds a doctor (Jude Law) who prescribes a succession of different drugs, one of which affects her behaviour in unpredictable and profound ways. It was fun, Soderbergh stresses, all the more so because he was savouring his last days on a film set. The commonly held idea that, as an artistically credible director, he alternates making a movie for himself with one for The Man is nonsense, he says. ''Nobody that actually makes anything, I think, would ever take that position,'' he says. ''Obviously, they're all for me. I don't spend two years on anything I don't want to make. Any movie I've made has been because of the challenge it offered me as a director, because it provides a new canvas.'' The Oceans films, for example, offered an opportunity to play with images that suggested a comic strip. ''I viewed them as Roy Lichtenstein panels, which was really fun.''

But there is such a thing as too much fun. Every now and then, Soderbergh lets slip a moment's rage against a film culture that wants nothing else. He doesn't blame 3D: that's just another tool, for good or ill. He doesn't blame the studio heads or investors, no matter how much he resents them in other ways. ''Audiences decide everything, for sure,'' he says. ''The people financing movies just react to what they feel the audience is telling them to do. I think that is pretty clear: if there were big money in making better movies, they would do that.'' The problem is that audiences have narrowed their demands to include only facile, preferably very loud, entertainment. ''I just think the reasons people go to the movies in the States has changed; I think the experience they are looking to have has changed,'' he says. ''And I don't know if that is just a residual effect of 9/11, and a lot of other things - the economy - but I do think they don't look to the movies for the same things that I did when I was growing up, which was not necessarily to always be escaping whatever reality I was living in, or to get answers to things, or just to be made to feel good all the time.''

When Contagion was released in 2011, he watched as audiences were infuriated by the dodgy whistleblower played by Law because they were unsure of his moral status. ''The fact that he created a sort of mixed reaction was viewed as a flaw in the filmmaking. Not, 'Oh, that's interesting, I'm not sure if this guy is an asshole or a hero','' he told New York magazine. ''People were really annoyed. And I thought, 'Wow, so ambiguity is not on the table any more.' ''You try and withstand that kind of force at your own peril. You can't change the audience, so you've either got to find a way to satisfy them in a way that doesn't make you want to take a shower, or move into a different medium, you know, where spending time to make a product that is distinct from other things and has an aspiration to engage and make the audience do some work is a good thing, not a bad thing.'' That could be television, where a weekly audience of up to 4 million households - which would be a disaster for a film release - is a roaring success. It will certainly be his studio and all its canvases. What does Soderbergh think his legacy will be? ''I don't think in those terms. You can't,'' he says. ''I've been very, very, very lucky that I have had creative control over the movies I've made, so I'm happy about that. At least the body of work is mine, whatever its faults are. And my attitude has been just to make stuff. To find reasons to say yes. It's an act of will trying to get these things done, but at least I left it all on the field.'' ■ Side Effects is now showing.