The principles of scientific and anthropological investigation were quickly adopted by early photographers, who found in these fields an objectivity and clarity ideally suited to the new medium.

The impulse to collect and order material is evident in August Sander's project, begun in the early 1920s, to document the character of Germany through portraits of its people.Prevailing class differences and social hierarchies are recorded and categorised in over 600 images, with an unflinching gaze. The photographs in this vast series are individually compelling, but it is in the accumulation of images that the fuller meaning emerges.

Comparison and classification is a theme that concerns a number of the artists in this exhibition. For Nicholas Nixon, the close focus of the family group - his wife and her sisters, photographed every year - provides the substance for a moving, comparative essay on the passage of time.

Fazal Sheikh, meanwhile, unpicks the dramatising clichés of refugee imagery with his dignified portraits that focus on individuals, their histories recorded in texts alongside the photographs. Like Nixon, Sheikh counters the instantaneity of the photograph by returning to the same subjects some years later, so complicating our immediate response.

Bernd and Hilla Becher’s subjects are not people but the disappearing architecture of our industrial past. Their typologies of grain silos, blast furnaces and coal mines draw attention to the overlooked beauty of these engineered structures.

Thomas Struth and Thomas Ruff have reinvigorated the tradition of portraiture for today’s audiences. Ruff’s mugshots of college friends, and Struth’s comparative images of family groups from around the globe share an almost anthropological level of scrutiny.