NEW YORK -- (AP) -- Irving Penn, whose photographs revealed a taste for stark simplicity whether he was shooting celebrity portraits, fashion, still life or remote places of the world, died Wednesday at his Manhattan home. He was 92.

The death was announced by his photo assistant, Roger Krueger.

``He never stopped working,'' said Peter MacGill, a longtime friend whose Pace-MacGill Galleries in Manhattan represented Penn's work. ``He would go back to similar subjects and never see them the same way twice.''

Penn, who constantly explored the photographic medium and its boundaries, typically preferred to isolate his subjects from their natural settings to photograph them in a studio against a stark background. He believed the studio could most closely capture their true natures.

Between 1964 and 1971, he completed seven such projects, his subjects ranging from New Guinea mud men to San Francisco hippies.

``Photographing a cake can be art,'' he said at the 1953 opening of his studio, where he continued to produce commercial and gallery work into the 21st century.

Thirteen of Penn's photographs are being auctioned Thursday at Christie's, including Guedras in the Wind, a 1971 image of two Moroccan women, with an estimated pre-sale price of $40,000 to $60,000.

Penn's career began in the 1940s as a fashion photographer for Vogue.

He stumbled into the job almost by accident, when he took a position as a designer in the magazine's art department in 1943. Staff photographers balked at his unorthodox layout ideas, and a supervisor asked him to photograph a cover design.

The resulting image, on the Oct. 1, 1943, cover of Vogue, was a striking still-life showing a brown leather bag, a beige scarf, gloves, oranges and lemons arranged in the shape of a pyramid.

He left the magazine in 1944 to join the military -- serving with the American Field Service in Italy and then as a photographer in India -- but returned to Vogue in 1946, taking travel assignments in addition to his fashion work.

In the 1950s, Penn moved into portraiture. He photographed not only the famous but also ordinary people. He published a series of pictures in 1950-1951 featuring plumbers, salesmen and cleaning women in New York City, Paris and London. The Getty Center in Los Angeles is exhibiting some of the photos.

His celebrity portraits included closely cropped images of Miles Davis, Spencer Tracy, Georgia O'Keeffe and Pablo Picasso, the last peering apprehensively from beneath a wide-brimmed hat. He once said that his formula was to photograph his subjects relentlessly, until they were forced to let down their guard.

Born in Plainfield, N.J., in 1917, Penn studied at the Philadelphia Museum School of Industrial Art from 1934 to 1938, and worked as an assistant at Harper's Bazaar in 1939.

Penn married fashion model Lisa Fonssagrives in 1950, and for decades afterward she remained one of his favorite subjects. She died in 1992.

They had a son, Tom. His wife also had a daughter, Mia, from a previous marriage.