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Known professionally as "Karsh of Ottawa," his 1941 photograph of Winston Churchill brought him worldwide prominence.

▲An American photographer and environmentalist, Adams remains one of the great pioneers of landscape photography, and is especially known for his black and white images of the American West.

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Technically brilliant, he co-developed a precise system of image-making called the Zone System to produce stunning work like 'Evening, McDonald Lake, Glacier National Park' (1942).

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Distinguished by her Depression-era wok for the Farm Security Administration, Dorothea Lange was one of the foremost documentary photographers of her generation.

▲One of the American photographer's most iconic images is 'Migrant Mother' (1936).

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Regarded by many as the world's greatest combat photographer, the Hungarian photojournalist covered five wars, including the Spanish Civil War, WWII, and the 1948 Arab-Israeli conflict.

▲This image shows a woman, with her baby whose father is German, and her mother jeered at and humiliated by crowds in Chartres after having their heads shaved as punishment for collaborating with German troops.

▲Besides working as a photographer, Stieglitz, an American citizen, was an enthusiastic promoter of modern art. He was instrumental in introducing many avant-garde European artists to the United States.

▲An early photographic success was this award-winning image, 'The Last Joke, Bellagio' (1887).

▲Another American photojournalist celebrated for his work for the Farm Security Administration during the Great Depression, Evans was also a writer and held down a position at Time magazine.

▲This image, 'Roadside stand near Birmingham, Alabama,' is typical of the Depression-era photographs Evans is known for.

▲A master of the photo essay, Hungarian-born Kertész based himself in Paris before emigrating to the United States in 1936 as the threat of war loomed in Europe.

▲His skills as a photojournalist are perfectly embodied in this simple study, 'Circus, Budapest' (1920).

▲Collaborating frequently with Kertész on several photographic projects, Steichen began his professional career as a fashion photographer, but is also highly regarded for his work as director of the Naval Aviation Photographic Unit (pictured) during WWII.

▲Moving in high society, the photographer's subjects included artists and authors. This image is called 'Henri Matisse and La Serpentine' (1909).

▲Multi-talented Parks was a photographer, musician, writer, and film director. He worked as a photojournalist in the 1940s through the 1970s

▲His image 'American Gothic, Washington, D.C.' typifies his coverage of the civil rights movement in the 1960s. Parks is also remembered as the director of the 1971 film 'Shaft.'

▲Picking up a camera in the late 1880s, Atget was an early pioneer of documentary photography. His specialist subjects were street photography and architecture.

▲The French photographer never received the recognition he deserved during his lifetime and it was only after his death that images like 'Organ Grinder' (1898) and many others were published.

▲One of the very first "celebrity" photographers, Cameron managed to capture many illustrious figures of the day during her short 11-year career as a portrait photographer.

▲Lewis Hine's raw, powerful images of child laborers in the early 20th century were instrumental in changing child labor laws in the United States.

▲Typical of his work is this haunting portrait 'Adolescent Girl, a Spinner, in a Carolina Cotton Mill' (1908).

▲Brady covered the American Civil War as one of the country's earliest photographers. He used a mobile studio and darkroom to shoot on location, in places that included the Antietam battleground.

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He also photographed many famous Americans of the era, including presidents Andrew Jackson, John Quincy Adams, and Abraham Lincoln, shown here on the day of Lincoln's Cooper Union Address (1860).

▲This English photographer is distinguished for his pioneering work in photographic studies of motion and, in particular, animal locomotion.

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He used multiple cameras to capture motion in stop-motion photographs. These were then projected as motion pictures. The image here depict's Muybridge's 'The Horse in Motion' (1878).

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Acknowledged as one of the greatest portrait photographers of the 20th century, the Armenian-Canadian photographer captured the personality of many notable individuals.

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The British photographer persuaded the likes of poet Lord Tennyson, naturalist Charles Darwin (pictured, 1868), and eminent scientist Sir John Herschel to sit for her.

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In this digital age of smartphone photography, it's easy to forget that photographs were once produced using glass plates and, later, film emulsion. Early pioneers of photography captured an extraordinary array of subject matter using techniques and processing methods that today appear simply archaic. But if it wasn't for these gifted and imaginative individuals, some of the most famous and groundbreaking photographs in the world would never have been taken.

Browse this gallery and focus on how the history of photography developed.