Philip Jones Griffiths (b. 1936) is a Welsh-born photojournalist known for his coverage of the Vietnam war. Griffiths studied pharmacy but started as a freelance photographer in 1961, traveling to Algeria in 1962. He arrived in Vietnam in 1966, working for the Magnum agency. 

Harry Morey Callahan (October 22, 1912 – March 15, 1999) was an influential twentieth century American photographer. Born in Detroit, Michigan, he began teaching himself photography in 1938. He formed a friendship with Todd Webb who was also destined to become a photographer. A talk given by Ansel Adams in 1941 inspired him to take his work seriously. In 1941, Callahan and Webb visited Rocky Mountain State Park but didn’t return with any photographs. In 1946 he was invited to teach photography at the Institute of Design in Chicago by László Moholy-Nagy. He moved to Rhode Island in 1961 to establish a photography program at the Rhode Island School of Design, teaching there until his retirement in 1977.

Joel Meyerowitz (born March 6, 1938 in the Bronx, New York City) is a street photographer who began photographing in color in 1962 and was an early advocate of the use of color during a time when there was significant resistance to the idea of color photography as serious art.

National Geographic Explorer’s documentary “Freelance in a World of Risk” featuring Ron Haviv of the VII Photo Agency.