Lives through the lens

An exhibition of work from photographers of the 1960s and 1970s is reminder, says Michael Glover, of the medium's vital role in bringing the powerful to account

Moments in time: 'Succession' by Raghubir Singh

Photography has become so thoroughly prostituted as a means of visual exchange that it is easy to forget that until relatively recently one of the most important consequences of fearless photographic practice was to tell the truth about power.

This group show at the Barbican focuses on the work of 12 photographers from around the world examining their photographic practice in relation to the historical moments through which they lived. The covert eye of the camera often shows us what the authorities do not want us to see: the injustice of life lived under apartheid; the scarring aftermath of the allied bombing of Japan; the brutish realities of the Vietnam war.

Photography, it has often been said, documents the world. This suggests that the photographer might be a dispassionate observer of neutral spaces, more machine than emotive being. Nonsense. Using a camera is the photographer's own way of discovering his or her own particular view. It is a point of intersection between self and world. The good photographer, in the words of Bruce Davidson, the man who fearlessly chronicled the fight for civil rights in America in the early 1960s, seeks out the "emotional truth" of a situation.

For more than half a century, David Goldblatt, born in the mining town of Randfontein of Lithuanian Jewish parentage, has been chronicling the social divisions of South Africa. Goldblatt's images are stark, forensic and pitiless, from the matchbox houses in the dusty streets of 1970s Soweto, to the lean man in the hat who is caught butchering a horse for food in a scrubland of wrecked cars. Goldblatt captures the day-to-day life of the Afrikaners: their narrow point of view, tenacious conviction of rightness and visceral bond with the soil. There is nothing demonstrative or rhetorical about his work. It is sober, and focused on the job in hand, as if reality is stark enough.

Boris Mikhailov, wild, impish and contrarian in spirit, turns photography into a subversive art form. Born in Kharkov in Ukraine under communism, his photographic montages represent an energetic fightback against the grinding tedium of accepted notions of conformity. He frames an image of a Kremlin tower in a circle of raw meat slabs. He reduces accepted ideas of beauty to kitsch. Underwear swings in the air beside a receding railway track. He mercilessly lampoons the fact that the authorities forbade the photographing of nudity.

Shomei Tomatsu has been preoccupied all his life by a single theme: the US occupation of Japan in the aftermath of its humiliating military capitulation. Born in 1930, he still lives in Okinawa, the island from which the Americans launched their B52s during the Vietnam war. His angle of view suggests a mixture of abhorrence with the invasion of an alien culture and a fascination with its consequences: a child blows a chewing gum bubble beside a street sign that reads "Bar Oasis". The image of the child is distorted in the bubble.

But this show is not all about cocking a snook at authority. It is also about aesthetic issues: the use of colour as a way of shaping a different kind of reality, for example. William Eggleston made his series of photographic portraits of ordinary people from Memphis, Tennessee, often at night, in the 1970s. These are seemingly casual and immediate moments of intimate engagement between photographer and subject. Until this moment, colour had often been used by the camera to glamorise. Not so here. Eggleston is especially good at registering the lonely decrepitude of objects – a jukebox on a Memphis wall; the resonance of an empty room in Las Vegas.

For Raghubir Singh, on the other hand, who is a contemporary of Eggleston and Mikhailov, colour is used to represent his native India in ways that display its spiritual richness. His practice feels like a covert criticism of a Western addiction to the monochromatic. By contrast, Singh's "Ganges Modernism" proclaims colour as an aspect of spirituality. There is such a dynamic visual clamour in his colour-suffused friezes of teeming humanity: a Rajasthani village bus stop is infested by peacocks; an old pilgrim is caught squatting against a brilliant red Ambassador car; people fly kites off the corrugated roofs of Ahmedabad as entire families clamber about the rising roof tops.

When photography first began to make its mark upon the world in the 1840s, painters took note. What threat would it pose to the art of painting? What new freedoms might it offer? More than 100 years later, the English photographer Larry Burrows caught images of the Vietnam war that look like history painting made anew, such is their dynamism, their intensity and their psychological impact — to such an extent, in fact, that they feel almost staged – a wounded sergeant is being led away to safety by his comrades. As he does so, he spots his dead commanding officer propped up nearby, and lunges in his direction.

There is much heroism in many of the stories behind this work. Li Zhensheng was a press photographer during the most frenzied years of the Cultural Revolution in China. He photographed what he was required to photograph – various "composite panoramics", for example – and entire sequences of "unauthorised" events, which he risked his life to capture.

We see demonstrations of various kinds, most notably the memorial gathering for the death of Mao in Harbin's People's Stadium, attended by half a million people, which was shot from the top of a fire-engine ladder; the public humiliation of wrongdoers, heads bowed, in dunces' caps; the denunciation of "bad characters"; and a sad cluster of cowed Buddhist monks in Harbin on 24 August 1966, holding up a banner that reads: "To hell with the Buddhist scriptures, they are full of dog farts."