PHOTOGRAPHY / Some knit: I take photographs: The actor Jeff Bridges has been playing double agent, taking a camera on location. David Thomson admires the results

LAST SUNDAY was a good day for Jeff Bridges. He was the cover story in the New York Times Magazine, billed as 'Hollywood's Most Underrated Actor'. That piece was pegged to the American opening of Peter Weir's Fearless, in which Bridges plays a man who survives a major air crash but lives in a state of shock so that he feels immortal. He was also in the middle of work on a new action picture, Blown Away, in which he is a bomb-squad officer.

Meanwhile, in Santa Monica, California, where Bridges lives, the Gallery of Contemporary Photography on Main Street opened an exhibition, Losing the Light, of pictures taken by Bridges during the making of some of his recent movies. And here's the intriguing thing: as an actor Bridges is underrated because he's unselfish and restrained - actors admire him, though the business says that Bridges can't carry a movie. But as a photographer, he's a knockout. It's as if his urge to be sensational had suddenly broken free.

Bridges regards this work as a hobby, a way of filling time spent waiting on a movie set: 'Some knit: I take photographs.' He calls them snapshots, and for years he used to guess the exposure (in which case, he has an electronic eye). But he does not mean to build a new career, or another art for himself. 'Taking photographs is a sort of entertainment for me, and I try not to sweat about it too much. I usually have my camera with me, and if I see something I'll take the shot.'

That spontaneity owes a lot to his camera, the Widelux, a gift from Susan, his wife of 16 years. He's had it on sets ever since, and the Santa Monica exhibition includes pictures taken on the sets of The Morning After, Tucker, Jagged Edge, The Fabulous Baker Boys, Texasville, The Fisher King, American Heart and Fearless. The Widelux delivers black-and-white pictures much longer than they are high: it's a 2.5:1 ratio, just like the classic CinemaScope frame from the 1950s. Bridges loves 'the idea that there is so much information in the negative. Many different worlds seem to be going on in a single shot.'

That catches the dynamic of his best pictures, which keep the glamorous intensity of the story and the untidy process that makes it in one sweep. You can see this in the driver's-eye view shot from Texasville. The structure of the car frames a flat stretch of Texas and the patient retinue of technicians. The picture's dial or plughole is an anxious face, that of director Peter Bogdanovich, composing the shot, striving to concentrate, staring into the potion of his dream - the final movie. There's another cramped panorama from Texasville, of Cybill Shepherd sitting up in bed ready for a shot, with Bogdanovich on his knees beside the bed talking to her, and a gaggle of crew off on another side of the frame - getting coffee, talking sports, wondering about the next job and whether this shot will get done in time for Mexican dinner if the talent doesn't get on. Shepherd looks haughty and fictional, and Bogdanovich seems in rueful prayer. Yet the crew is shabby, happy, bored, indifferent and weary. They know that the saints of the show have to get desperate first - that's glamour.

Bridges cherishes those islands of disarray, movie sets, where a pit of lucid brightness can suddenly emerge from the lights, the cables, the flats, reflectors, baffles and scrims. You spot the slender beauty of Michelle Pfeiffer or Isabella Rossellini, but they're nearly lost in the throng of fat, bearded gaffers and grips, their belts ringed with tools, and the make-up girls, with flirty glances, touch-up brushes and sotto-voce dirty jokes. In the Tri-X erotics of these pictures there lurks the dangerous thrill of set romances, collisions of rapture or sex between otherwise domesticated people who are off for a few weeks, not just in Texas or Seattle, but on a story, a picture. Then there's fatigue that shows like broken bones in a face, the strain of staying lovely and sane in the nightmare junk room of filming.

These people are supposed to be having a good time - and they grin for the camera (it might be a pest if it wasn't the star holding it). In the ordinary pictures you feel Bridges doing his duty, getting everyone on the shoot for the kind of album he distributes after the last wrap. But in his best work he captures the loneliness in the crowd and the wistfulness they all know, that soon this escape, this hell, will be over.

There's a picture from The Morning After, of Jane Fonda amid the clutter of the process, showing her age, her sadness and the exhaustion; it's the most tender glimpse of the actress I've ever seen. Then there's Karen Allen beside some windswept highway on Starman, sitting in her chair, knitting an eternal sweater, while a truck goes by behind her on a road turned into an arc by the wide-angle lens. There's a desolation in that picture to match an Edward Hopper painting. Then, from Fearless, there's a superb study of pools of light and shadow, the cubism of scenery and reflectors with, far away, Rosie Perez, standing in a glade of light, trying to find her character's distress.

Bridges' eager eye and his understanding of movies make one realise how lousy production stills are these days. I mean the pictures handed out for publicity purposes. No one now doing that job feels the passion Bridges sees. He has portraits of unmatched directness: cameraman Vittorio Storaro taking a light reading beneath the mock-up Spruce Goose for the Howard Hughes scene in Tucker; Michelle Pfeiffer, surrounded by dark, putting on her lipstick - did the Widelux love her, or was Bridges smitten, too? - and a picture of a grinning Texan in a white hat against a background of endless scrub, with Bridges' hand-written and self-effacing caption: 'Rusty Lindeman - the 1st day of shooting. I was really in trouble. I had no idea what my character, Duane Jackson (Texasville), should be like. When into my trailer came this oilman who owned the land we were shooting on. He was kind enough to lend me his hat, pants, and the pens and cards in his pocket. Rusty saved my ass.'

Which is why, on a film location, you must never bat an eyelid if you come upon a guy sitting in a trailer without his pants, waiting. Every sacrifice serves the story. Jeff Bridges and his Widelux have done a richer job of conveying that daft pressure than photography has ever managed. To look at his pictures, it's hard to think there isn't more still in Bridges - like a director, one day?

'Losing the Light: Photographs from the Set' continues at the Gallery of Contemporary Photography, 2431B Main Street, Santa Monica, California (0101 310 399 4282) to 22 Nov.

(Photographs omitted)