Photography: Lives through the lens

The Barbican's new exhibition brings together work from 12 of the most important photographers of the 1960s and 1970s. A reminder, says Michael Glover, of the medium's vital role in bringing the powerful to account

Photography has become so thoroughly prostituted as a means of visual exchange, available to all or none for every purpose under the sun (or none worthy of the name), 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, including Vietnam, India, the US, Mexico, Japan, China, Ukraine, Germany, Mali, Japan and South Africa, examining their photographic practice in relation to the particular 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 bleak injustice of life lived under apartheid; the scarring aftermath of the allied bombing and occupation of Japan; the brutish day-to-day 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 angle of view. It is a point of intersection between self and world. There is no such thing as a neutral landscape; there is only ever a personal landscape, cropped by the ever quizzical human eye. The good photographer, in the words of Bruce Davidson, the man (well represented in this show) who tirelessly and 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, treeless streets of 1970s Soweto, to the lean man in the hat who is caught wearily and systematically butchering the coal-merchant's dead horse for food in a bleak scrubland of wrecked cars. Goldblatt captures the day-to-day life of the Afrikaners: their narrowness of view; that tenacious conviction of rightness; the visceral bond with the soil. There is nothing demonstrative or rhetorical about his work. It is utterly, monochromatically sober, and quite subtly focused on the job in hand, as if he wishes to say to the onlooker that reality is quite stark enough.

Boris Mikhailov, wild, impish and contrarian in spirit, turns photography into a self-consciously subversive art form. Born in Kharkov in Ukraine under communism, his photographic montages represent a ferociously energetic fight-back against the grinding dullness, drabness and tedium of accepted notions of conformity. He frames a sugary image of a Kremlin tower in a circlet of slabs of raw meat. He reduces accepted ideas of beauty to kitsch. Underwear swings gaily in the air beside a receding railway track. He mercilessly lampoons the fact that the authorities forbade the photographing of nudity. This is the not-so-gentle art of blowing red raspberries.

Shomei Tomatsu has been preoccupied all his life by a single theme that he circles around obsessively: the American 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 utterly alien culture and a fascination with its practical consequences: a Japanese child blows a huge 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 (and especially the movie camera), not to particularise but to glamorise. Not so here. Eggleston is especially good at registering the lonely decrepitude of objects – a jukebox on a Memphis wall; the reptilian patina of a rusting street light; 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 put on display its spiritual richness like so many toothsome sweets on a counter. His practice feels like a covert criticism of a Western addiction to the monochromatic and all that seems to be saying to us, existentially, about the soulessness of Cartier-Bresson's images of the loneliness of Paris. 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 – a dhoti-wreathed, self-absorbed, bespectacled bag of bones – is caught squatting against a brilliant red Ambassador car; kites fly off the corrugated roofs of Ahmedabad as entire families clamber about the rising roof tops, egging on the dots in the sky to yet greater heights.

When photography first began to make its mark upon the world in the 1840s, painters took note. What threats 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 and feel like a species of history painting made anew, such is their dynamism, their intensity and their psychological impact, to such an extent, in fact, that these moments of conflict, large in format, 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. That terrible moment – a yearning to recognise the continuing, underpinning authority of a dead man – chills to the bone. Larry Burrows himself was shot down over Laos in 1971.

There is much heroism in many of the stories behind this work. Li Zhensheng (born in 1940) 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, which in their breadth of view seem to pay homage to the Battleship Potemkin – and entire sequences of "unauthorised" events, which he risked his own life to capture. We see public 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."

'Everything Was Moving: Photography of the 60s and 70s', Barbican Art Gallery, London EC2 (020 7638 8891, www.barbican.org.uk). Until 13 January