Mr. Eppridge spent eight years on the staff of Life, the weekly magazine noted for its striking photography. He covered many of the seminal events of the time, including the civil rights movement, the war in Vietnam, the Beatles’ arrival in the United States and the Woodstock music festival in New York.
His most searing images came from his coverage of Kennedy’s campaign to win the 1968 Democratic presidential nomination. He followed the candidate, then a U.S. senator from New York, across the country as throngs of people crowded close to hear to him speak and to shake his hand.
“He ignored me,” Mr. Eppridge said of Kennedy in a 2008 interview with NPR. “And by ignoring me, he allowed me to photograph moments that were really true moments; not set up, not photo ops, but just moments that happened, and I loved it.”
After Kennedy won the California primary, he addressed a hopeful crowd of supporters in the early morning hours of June 5, 1968, at the Ambassador Hotel in Los Angeles. He left through the kitchen, shaking hands with hotel workers.
Mr. Eppridge was about 12 feet behind Kennedy when he heard gunfire — eight shots, he distinctly recalled. He then saw Kennedy lying on his back, his arms outstretched, as a busboy, Juan Romero, kneeled over him.
Using black-and-white film, Mr. Eppridge instinctively began to snap pictures. There was barely enough light to illuminate the side of Kennedy’s face, as Mr. Eppridge captured a chillingly unforgettable image.
“I was standing there, looking,” Mr. Eppridge told NPR, “and suddenly realized that what I was seeing there was an icon, almost. It was almost like a crucifixion.”
He would later photograph mourners lining the tracks as Kennedy’s funeral train made its slow way to Washington. But it was 25 years later, when he was preparing the first of two books about Kennedy, before Mr. Eppridge could bear to look at his contact sheets from the Ambassador Hotel.
“I have been living with this thing 40 years now,” he told the Baltimore Sun in 2008. “There’s not a day that goes by that I don’t think, somehow, about him. Or that campaign. Or the consequences of his assassination.”
Guillermo Alfredo Eduardo Eppridge was born March 20, 1938, in Buenos Aires, where his American father was a chemical engineer with DuPont. He returned with his family to the United States as a child and graduated from a private school in Delaware.
He began taking photographs in high school and was twice named college photographer of the year before graduating in 1960 from the University of Missouri. He went on a nine-month trip around the world for National Geographic, then freelanced before joining Life.
One of his first assignments was to spend six days with the Beatles on their first trip to the United States in February 1964. A collection of his photographs of the time, most of them never before seen, will be published next year in the book “The Beatles: Six Days that Changed the World.”
Mr. Eppridge was an expert in equipment, lighting and other technical elements of photography, but a greater talent may have been the way he immersed himself in a story and earned the confidence of his subjects.
In the summer of 1964, he approached the family of James Chaney, one of three civil rights workers killed by white supremacists in Mississippi. He attended Chaney’s funeral, taking a picture of the tear-stained face of his younger brother as he leaned close to his mother.
“Bill was a very likable guy, which is a big part of getting any kind of access,” said Bill Snead, a former Washington Post photographer who knew Mr. Eppridge for 50 years. “He was sincere, and he didn’t just run in and run out. He had empathy for his subjects.”
One of Mr. Eppridge’s most remarkable stories came in 1965, when he and Life reporter James Mills spent more than two months with a married pair of heroin addicts on New York’s Upper West Side. The story, “The World of Needle Park,” was a penetrating and often painful look at a subculture that few people had ever seen.
“Mills and Eppridge became denizens of the junkie world,” managing editor George P. Hunt wrote in the Feb. 26, 1965, issue of Life. “They learned the language, which they had to speak with meticulous care or be branded as outsiders.
“They picked up some of the junkie’s uncanny ability to spot a ‘narco’ (narcotics detective) . . . and they frequented fleabag hotels, three of which unceremoniously threw them out,” Hunt continued. “Eppridge, in fact, came so much to look the part that he was picked up by the narcos in a hotel lobby; they thought he had stolen both his cameras and Life credentials and were about to haul him off when Mills (who looks more like a cop) came to straighten things out.”
The article was the inspiration for the 1971 film “The Panic in Needle Park,” starring Al Pacino and Kitty Winn.
After Life stopped publishing weekly in 1972, Mr. Eppridge worked for Time and Sports Illustrated, covering America’s Cup races and the Olympic Games, retiring in 2006. He often spoke at photography seminars across the country and received many honors, including the highest award of the National Press Photographers Association in 1996.
Survivors include his wife of 16 years, Adrienne Aurichio of New Milford, Conn.; and two sisters.
After the 1968 assassination of Bobby Kennedy, Mr. Eppridge, retreated from the world of politics and conflict. He spent three months in the mountains of the West, photographing wild horses. He never again covered a campaign or became close to another political figure.
“If you photograph a politician,” Mr. Eppridge told the Palm Beach Daily News in January, “you want him to be a good man and someone you trust. That was Bobby. I could not find another Bobby.”