Final answer:
Ansel Adams and Dorothea Lange contributed significantly to the art of photography. Adams is famous for his black-and-white landscapes and technical contributions, while Lange's documentary photography highlighted social issues.
Step-by-step explanation:
Photographers Ansel Adams and Dorothea Lange made essential contributions to the development of photography. Ansel Adams is renowned for his stunning black-and-white landscape photographs which have come to symbolize the American West. Adams' technical expertise with the camera and his development of the Zone System, which allowed for greater control over exposure and contrast in images, revolutionized the field of photography and its potential as a form of fine art.
Dorothea Lange, on the other hand, used her camera as a tool for social change. Her powerful images from the Great Depression, especially the iconic 'Migrant Mother', brought attention to the plight of the poor and dispossessed and highlighted photography's capacity to influence public opinion and policy. Lange's emphasis on humanizing her subjects laid the groundwork for documentary photography as a potent and empathetic medium.
In the early 20th century, both Adams and Lange, through their contrasting styles and subject matters, played pivotal roles in establishing photography as a legitimate and expressive art form.