Why, exactly, did she want to position Abraham under a swampy tree? 'Because of his shirt,' says Liu, as if this is the most obvious reason in the world (Abraham's shirt, if you peer closely at it, has a busy, leafy pattern). 'And because of his energy and roots.'

Two facts are apparent from this collection of Liu's work: her enthusiasm for what she does as a photographer and her friendship with those she has worked with as a singer. You look at the strange contortions and happy idiosyncrasies she has captured in some of these paired black and white images - a world in which everyone seems to march to a different tune, not slightly but emphatically - and think that only a high degree of mutual trust could achieve such results. 'I love these people so much,' says Liu, flicking fondly through her portfolio. 'I always got the idea of what to do when I looked at the person and asked them, 'What do you want to be? Where do you want to go?'' The answers were, like jazz itself, unconventional, varied and improvised. Peter Scherr went to the sea at Sai Kung, not far from Liu's village, and stood in the water, plucking at his double bass; then he placed the instrument on his head. 'We were leaving and I had my camera in my bag, but I said, 'Oh my god, it's the best one.' It was just like jazz - about the moment.'

Another double-bass player, Sylvain Gagnon, felt his moment required utter nudity amid the costumes of Greg Derham's House of Siren. 'I said, 'Good idea!'' says Liu. 'I like them to feel they can be themselves completely, as if I'm not there.'

Meanwhile, the drummer Robbin Harris is seen, like an extra from Lord Of The Rings, flinging himself into the sky against a pastoral setting, clutching a cymbal as if it were a magic talisman. In another shot, he sits, brooding without his instrument, among vegetation. 'It's more about the person than whatever instrument he plays,' says Liu. 'The instrument says something ... but sometimes that goes without saying.'

In the same way, the Filipino pianist Yoyong Aquino Jnr devotedly plays the surface of water: you can almost hear his passion. 'I asked him to wear a tuxedo, because he plays in lounges, in hotels, and I asked him to play in the wilderness,' says Liu. 'He decided not to wear shoes. He said, 'This reminds me of home, in the Philippines', and then he ran away, and I chased after him, and he went into the sea and I did too, trying to capture his spirit. He was like an eagle flying. This is him, an amazing person.'

As you might expect from a musician producing images, Liu is good at conveying the visuals of sound. There's Eugene Pao, lit up like a Christmas tree ('because he's a star') with a force field of bright twinkles issuing forth from his guitar; Allen Youngblood, his tie flying away in the slipstream of his chords (an effect which was achieved with a little help from tape and wire); Guy Le Claire literally playing air guitar (it's apparently hurtling towards him, on the verge of near concussion - another special effect using wire).

Le Claire, an Australian who encouraged Liu to take up singing professionally in 1997, a few years after she'd returned to Hong Kong from the US, is now living in Yangshuo, near Guilin. 'He's spiritual, man,' says Liu who was educated at the German-Swiss International School in Hong Kong, Bedgebury School in Kent, and Boston University, and can sound very English and very American in the same breath. 'He needed the space. He only comes down here once a month now.' This sort of refrain - 'He's gone ... he's not here any more ... he's left' - is one Liu finds herself frequently uttering as she discusses her images.

The project, which she started 18 months ago, was never intended to have any elegiac force, but harder times have intervened, and it turns out that she has accidentally charted the passing of a particular jazz era in Hong Kong. In Slightly Out of Tune - an exhibition that was originally intended to be shown earlier in 2003 - she has, unintentionally, compiled a history of loss. It's not only the people who have moved on. One of her photographs is of the trumpeter John Hubbard, looking like Marlon Brando, sitting in the now-defunct Jazz Club. 'It was taken right before the Jazz Club went,' she says, looking at Hubbard's old habitat with nostalgia. 'He used to go there every day to do his crossword and have a beer. That was his tradition. Now - that's it. Gone.' (In case this sounds ungrateful, she says: 'I'd like to thank Allan Zeman [the building's landlord] for supporting it for a very long time. It's difficult. You don't make a lot of money with jazz.')

Her own musical schedule has, naturally, been affected by this situation. 'I used to perform twice a week,' she says. 'Now, it's twice a month. The jazz scene is not very healthy in Hong Kong. We've lost a lot of venues, which is very upsetting.' Can photography fill that gap? 'No. I use the time to practice and to work hard, and hopefully I'm recording an album in February.' So if a bad fairy made her choose between singing and photography ... Liu suddenly looks genuinely agonised and bursts out: 'Cannot, cannot. That would be so painful. Because they're actually the same thing - a way of expressing myself. There's so much to learn in both of them. It's hard and it's important because I love them so much.'

There is only one woman in her jazz portfolio so far - Eugene Pao's singer girlfriend, Angelita Li, sensually floating amid white lilies - but Liu, at the time of this interview, was working up to the prospect of photographing herself. 'It'll be last- minute improvisation,' she says. 'I'll be interested to see it. It's very challenging to photograph yourself and, at the moment, I have no ideas. It's an absolute blank.' (Which it evidently remained. On New Year's Day, the eve of the exhibition opening, Liu finally decided not to include her own image - 'But I'm in there somewhere, within those pictures.')

She pauses, wanting to sound an upbeat note. 'I hope people will have a good time looking at all the photographs, all those good memories. These are the moments of the past - but there will be new moments in the future.'

Elaine Liu will perform with some of the musicians photographed in the exhibition at an All-Stars Party at the club at 10pm on January 17. Free to members; $80 admission for non-members includes one drink.