Although he has been one of the most consistently interesting and intelligent painters working in Ireland from the late 1980s onwards, Mark Joyce has been a notably quiet presence on the scene. He is someone who is highly regarded by peers, and by a relatively small circle of art lovers, rather than a generally familiar name. That has to do with his own natural reticence - he is disarmingly critical of his own work, which he discusses with wry, self-deprecating humour - and also, perhaps, with the subtle, under-stated nature of that work, which tends to be small in scale, oblique in approach and to favour close mid-tones rather than eye-catching contrasts.

Now, in his latest exhibition, folk forms (a title borrowed from a Charles Mingus album), which opens on Friday at the Green on Red Gallery, he has turned from painting to photography. Why? "I bought a camera," he explains. "I haven't painted for about a year and a half. In that time, I've taken the camera everywhere - it's a beautiful thing, a medium-format Bronica - and taken photographs of the kind of subjects I've always painted. So the subject-matter is the same."

The subject-matter is mostly located in the midlands. In fact, originally he was thinking of calling the show Midlands Gothic, "but I thought it was too definite, too specific". For the past six years, he has travelled back and forth on the same midlands route between Dublin and Sligo, where he teaches in the RTC. "The midlands have a certain kind of image," he smiles. "Not a particularly flattering image, but I didn't have that in mind."

He hopes that the photographs will create a cumulative sense of the Irish midlands as "a gothic northern landscape", both familiar and strange, with dense clumps of conifer forest, vast expanses of open peatland, shrines and superstitions, odd, improvised structures and weathered caravans - "a peripheral place on the edge of Europe". He was trying to re-imagine the heart of Ireland as "a dark, woodland region", an archetypal northern landscape on which our hold is more tenuous and temporary than we would like to imagine.

He tried to avoid cliche. "I could have photographed bungalows" or various other kinds of kitsch, but "it seemed too obvious and I didn't want to make a sociological study. I wanted to create lyrical images".

Often the offbeat lyricism emerges in the interaction between people and the natural environment, which produces forms that, beyond their apparent normality, are actually quite strange, even surreal. One image depicts a high-sided trailer parked in a flat landscape, its panelling coloured and textured by exposure to the weather. The subject becomes not the trailer but the picture the weather has made by its action on the metal.

"It's like a painting with wheels on the end parked in the landscape," Joyce agrees, and then adds: "I found I was photographing a lot of paintings."

He grew up on a farm above Tallaght. His mother, Kitty Joyce, runs the famous knitwear shop, Cleo's, in Kildare Street. His father still farms. "He's been planting a lot of trees in the last few years," Joyce says.

He has no doubt that his fascination with the interaction between people and environment comes from his childhood experience of living in "an odd, unfinished landscape, between urban and rural, forever changing. My imagination was formed by those spaces and places. For me, the landscape that has been worked is always more interesting than the untouched landscape. Culture is stronger than nature. I like strained urban spaces like the Huguenot cemetery (on Merrion Row in Dublin), crammed in between city blocks, or a piece of countryside that has a quarry cutting through it."

He hasn't, he emphasises, abandoned painting, however. "I don't think there's any relevance to the photography versus painting debate that was current back in the 1990s. I prefer shows where painting is seen in relation to photography, where things are mixed, the way you see a big Andreas Gursky photograph next to paintings at the Tate Modern, for example. There isn't a conflict. I see myself as someone who makes images, at the moment with light in a camera, but I wouldn't rule out painting again in a year of two."

As regards his own painting, though, he did feel he had reached a dead end. "I felt I'd gotten too familiar with my own way of doing things. For me, painting is about putting down skins of liquid colour until they seem right for you. When you're doing that, you're constantly creating spaces with paint. I suppose I got tired of the responsibility of playing God. I felt I was going a bit blank."

After graduating from NCAD, he went on to do an MA in London. "That turned me upside down. I learned about contemporary art by being there, close to so many terrific people. Chris Ofili was a student, for example. I was aware of people like Peter Doig, who was exceptional in being able to handle narrative. "I think a problem with English painting at the moment is that the narrative is about the material, it's all about paint. I found I had more in common with people from the Indian subcontinent, or from elsewhere, like Doig from Canada, because they could identify with narrative apart from the material."

Most painters he knows, he points out, have photographs or reproductions in their studios and use them in some way or another in their work. "I've always had photographs around the studio, including things tacked on the wall and a big pile of National Geographics." Painters like Doig and the Belgian Luc Tuymans have no compunction about using photographs as a primary source. So Joyce didn't feel at all estranged from or antagonistic to photography. Nor did he take it for granted.

"I was a bit worried about the technical aspects of not having any formal training. If a photographer said you've done such and such wrong, then I'm sure I have. I feel I'm using the medium almost in a naive fashion, in a painterly way."

In fact, he has been quite adventurous technically. In exploring the landscape, he was also exploring the medium. A study of an island on a lake is a blur, taken completely out of focus but strikingly atmospheric. He also tried, as he puts it, "shaking the camera around a bit, swilling the light around inside. Most of the time you get nothing, but occasionally it's absolutely right".

One of the main differences between painting and photography for him has been the reintroduction of the horizon line. "That disappeared from my painting about eight years ago when I went to London, and dealing with it again has been difficult." He's been trying to find ways to fight against it in the photographs. Discussing his painting, he borrows the Japanese term ukiyo-e, pictures of the floating world, cut adrift from the tyranny of the horizon line and classical perspective.

He sees his paintings as floating world images. "I'm happiest when things don't make sense spatially. In my painting, I've always played with the figure/ ground relationship by subverting it and reversing it."

The biggest challenge in photography is managing to do something similar working with just light, shutter speed and aperture. For the moment, he is happy to try and do just that. "It's wonderful to spend a couple of hours framing up a composition and figuring out the light, in making a picture.

"There are no real financial rewards in being an artist," he reflects. "So you might as well enjoy the freedom of pushing images around."

folk forms: photographs by Mark Joyce is at the Green on Red Gallery from November 24th to December 23rd.