Question: Who is the photographer associated with the New York School of Photography whose used his camera as a tool for social reform.

Context paragraphs:
Leonard Rosenfeld: Leonard Rosenfeld (December 14, 1926 – December 2, 2009) was an American expressionist artist who was born in Brooklyn, New York.  In the Post-World War II era, Rosenfeld associated with a group of artist known as the New York School.  His contemporaries and prominent New York School artists included Willem de Kooning, Franz Kline, Arshile Gorky, Mark Rothko, Clyfford Still, and Robert Motherwell.

New York School of Applied Philanthropy: The New York School of Applied Philanthropy, originally opened as a six-week summer program in New York City in 1898, was the first higher education program to train people who wanted to work in the field of charity, including child development and youth work, in the United States.  Becoming a part of Columbia University in 1904, it was the first school of social work in the United States.  The school was inaugurated by Mary Richmond, a prominent early 20th century child rights activist.  Alice Paul, one of the foremost advocates for woman at the end of the Progressive Era, was one of the first graduates of the school.  The school changed name in 1917 to the New York School of Social Work.

Joseph Rowntree (philanthropist): Joseph Rowntree (24 May 1836 – 24 February 1925) was a Quaker philanthropist and businessman from York, England.  Rowntree is perhaps best known for being a champion of social reform, partner and friend of Charles Booth, and his time as a chocolatier at family business "Rowntree's", one of the most important in Britain.  Even as a powerful businessman, he was deeply interested in improving the quality of life of his employees; this led to him becoming a philanthropist, pursuing many charitable causes.  In 1904 he created three trusts, the Joseph Rowntree Village Trust (JRVT) which was originally set up to build and manage the garden village of New Earswick, the Joseph Rowntree Charitable Trust (JRCT) and the Joseph Rowntree Social Services Trust (JRSST).  The latter two were both set up to effect social reform, the difference between them being that whereas the Charitable Trust was set up as a charity, the Social Services Trust was set up as a limited company so that if necessary it would be able to undertake social and political work not legally allowed by a charitable Trust.  He suggested that only the JRVT would be permanent but in fact all the trusts are still in existence although the Social Services Trust has changed its name to the Joseph Rowntree Reform Trust and with the separation of the Joseph Rowntree Housing Trust from the Village Trust in 1968, there are now four trusts that exist today.

Dore Ashton: Dore Ashton (May 21, 1928 – January 30, 2017) was a writer, professor and critic on modern and contemporary art.  She was born in Newark, New Jersey.  She was the author or editor of more than thirty books on art, including "Noguchi East and West", "About Rothko", "American Art Since 1945", "The New York School: A Cultural Reckoning" and "Picasso On Art".  Ashton also contributed to many publications including Art Digest and worked as an art critic at the New York Times.  Ashton was one of the New York art critics who championed the New York School, whose members also included Harold Rosenberg and Barbara Rose.  Ashton's 1983 work on Mark Rothko, "About Rothko", remains a source of much discussion about the artist.  Ashton's most recent book, "David Rankin: The New York Years", on artist David Rankin was released in July 2013.

New York school of photography: The New York school of photography is identified by Jane Livingston as "a loosely defined group of photographers who lived and worked in New York City during the 1930s, 1940s and 1950s" and who, although disinclined to commit themselves to any group or belief, "shared a number of influences, aesthetic assumptions, subjects, and stylistic earmarks".  Livingston writes that their work was marked by humanism, a tough-minded style, photojournalistic techniques, the influence of "film noir" and the photographers Lewis Hine, Walker Evans, and Henri Cartier-Bresson; and that it avoided "the anecdotal descriptiveness of most photojournalism" and the egoism of American action painting, and indeed that it was remarkably little influenced by contemporary painting or graphic design (even though a number of its exponents had direct experience of these).  Livingston selects as key exponents of the New York school of photography Diane Arbus, Richard Avedon, Alexey Brodovitch, Ted Croner, Bruce Davidson, Don Donaghy, Louis Faurer, Robert Frank, Sid Grossman, William Klein, Saul Leiter, Leon Levinstein, Helen Levitt, Lisette Model, David Vestal, and Weegee.

Lewis Hine: Lewis Wickes Hine (September 26, 1874 – November 3, 1940) was an American sociologist and photographer.  Hine used his camera as a tool for social reform.  His photographs were instrumental in changing child labor laws in the United States.

Joe Brainard: Joe Brainard (March 11, 1942 – May 25, 1994) was an American artist and writer associated with the New York School.  His prodigious and innovative body of work included assemblages, collages, drawing, and painting, as well as designs for book and album covers, theatrical sets and costumes.  In particular, Brainard broke new ground in using comics as a poetic medium in his collaborations with other New York School poets.  He is best known for his memoir "I Remember", of which Paul Auster said: “It is . . . one of the few totally original books I have ever read.”

Saul Leiter: Saul Leiter (December 3, 1923 – November 26, 2013) was an American photographer and painter whose early work in the 1940s and 1950s was an important contribution to what came to be recognized as the New York school of photography.

James Schuyler: James Marcus Schuyler (November 9, 1923 – April 12, 1991) was an American poet.  His awards include the Pulitzer Prize for Poetry for his 1980 collection "The Morning of the Poem".  He was a central figure in the New York School and is often associated with fellow New York School poets John Ashbery, Frank O'Hara, Kenneth Koch, and Barbara Guest.

Lida Moser: Lida Moser (August 17, 1920 – August 12, 2014) was an American-born photographer and author, with a career that spanned more than six decades, before retiring in her 90s.  She was known for her photojournalism and street photography as a member of both the Photo League and the New York School.  Her portfolio includes black and white commercial, portrait and documentary photography, with her work continuing to have an impact.

Supporting paragraphs: New York school of photography Lewis Hine
Answer: Lewis Hine