<P> Alfred Stieglitz ( January 1 , 1864 -- July 13 , 1946 ) was an American photographer and modern art promoter who was instrumental over his fifty - year career in making photography an accepted art form . In addition to his photography , Stieglitz was known for the New York art galleries that he ran in the early part of the 20th century , where he introduced many avant - garde European artists to the U.S. He was married to painter Georgia O'Keeffe . </P>
who was the photographer that was the leader and catalyst for photography as an art form
Alfred Stieglitz