Ansel Easton Adams ( February 20 , 1902 â `` April 22 , 1984 ) was a legendary American photographer and environmentalist , best known for his black-and-white photographs of the American West and primarily Yosemite National Park . Ansel Easton Adams ( February 20 , 1902 â `` April 22 , 1984 ) was an American photographer and environmentalist , best known for his black-and-white photographs of the American West , especially in Yosemite National Park .