(CBS News) NEW YORK -- The White House announced Wednesday that President Obama will mark the 50th anniversary of the March on Washington later this month with an address from the Lincoln Memorial, where Martin Luther King, Jr. delivered his "I Have a Dream" speech. Many of the images we have of the civil rights movement were captured by the man you're about to meet.
The South was simmering when Bruce Davidson went there in 1961 as a young photographer out of New York. He admitted he didn't know what he was getting into.
"I suddenly felt a little scared when the soldiers had fixed bayonets and live ammunition," he recalled. "And the police ... everyone was hostile."
In Alabama, he rode the bus with the Freedom Riders as they drove across the South to protest segregation.
in Birmingham, he photographed two white officers restraining a black woman in front of a movie theater playing "Damn the Defiant."
"You can see the police are twisting her arm," said Davidson, describing the photo.
Davidson snapped a picture of a woman waiting in a paddy wagon. "It's just the dignity of this woman being arrested," he said of the photo.
Nearby, a policeman holds a confiscated sign reading: "Kruschev can eat here, why can't we?"
"I was skinny, I was quick, I was fast and the cops couldn't catch me," said Davidson, who acknowledged that police tried to stop him. "Once they kicked me out of town in the South. They said, 'You're an agitator' or 'You're a Communist.'"
Davidson's civil rights photographs are being shown this summer at the Howard Greenberg Gallery in New York. At 79, he's now one of the country's most acclaimed photographers. In the Sixties, he was earning his living on fashion shoots. He had a contract with Vogue, but he gave it up to cover the civil rights movement.
"I needed to feel what I was doing was worth it," he explained.
Davidson spent four years in the South. "I don't shoot and run," he said. "I very often go back to my subjects."
He wanted to get close -- but not too close: "I stayed aware from meeting Dr. King. Every photographer in the world wanted to be his best friend ... I wanted to see who he really was and what was happening to him."
He said he probably took 5,000 photos of the South. His pictures gave people a new understanding of what was happening. They were a revelation -- even to him.
"I changed," he admitted. "Definitely."
Bruce Davidson's photographs would change how we saw our own country.