Harry Callahan

He is a photographer I very much admire.  He was self-taught, but arrived to such a level that he was invited by László Moholy-Nagy to teach at the Institute of Design in Chicago.  He taught at the Rhode Island School of Design for a very long time.  Here is an excerpt from Wikipedia that sums up what I admire about this man:

Callahan left almost no written records—no diaries, letters, scrapbooks or teaching notes. His technical photographic method was to go out almost every morning, walk the city he lived in and take numerous pictures. He then spent almost every afternoon making proof prints of that day's best negatives. Yet, for all his photographic activity, Callahan, at his own estimation, produced no more than half a dozen final images a year.