John Dominis, a Life magazine photographer who was known for capturing celebrities, wild animals and presidents at their unguarded best, and who was caught off guard himself while taking his most famous picture — of two American medal winners raising black-gloved fists at the 1968 Olympics — died on Monday at his home in Manhattan. He was 92.

The cause was a heart ailment, said his daughter, Dori Dominis Beer.

Mr. Dominis was a star among a stable of star photographers at Life, the nation’s most popular picture magazine, from 1950 until it ended weekly issues, in 1972.

Ingratiating, self-effacing and ruggedly handsome, he was often assigned to photograph people who preferred not to be photographed. He spent a month in 1963 with the actor Steve McQueen (nearly feral in his aversion to publicity), who was not yet the superstar he became. He persuaded Frank Sinatra to indulge him for three months in 1965 while he went inside his prickly circle of friends, family, drivers and handlers to photograph his life.