This show contains a revelation. Robert Capa, the Hungarian war photographer and founder of Magnum, the photo agency, famous for his Spanish Civil War photograph, Falling Soldier, is given the lion’s share of the upstairs gallery space and the ground floor is occupied by contemporary artists’ video film and stills from Afghanistan and Iraq, but the undisputed star of the show is the little-known Gerda Taro, who worked on the front line of the Spanish Civil War.

Taro was the first woman known to shoot pictures in battle and the first to die in action – in Spain in July 1937 at the age of 26 (Capa was to die in 1954 while on assignment in the First Indochina War). Born Gerta Pohorylle to a Polish-Jewish family, she was in Paris when she fell in love with André Friedmann. They later changed their names to Gerda Taro and Robert Capa.

When the Spanish Civil War broke out the couple, who were sympathetic to the republican cause, went to Barcelona to photograph frontline action. Taro learnt her craft alongside Capa and her work, seen here for the first time outside the US, is mostly in an enticing square format. It is full of life and energy. Taro shot uniformed militiawomen standing in the sun, soldiers creeping through rough grass or crouching behind heavy artillery. Her eye developed fast and she experimented with different styles, notably the heroic aesthetics of Soviet Socialist Realism, using abrupt angles and perspectives and raking light.

In 1936 she took the portrait of a militiawoman in training on a beach. The woman kneels in profile, in high heels and tailored trousers, as she takes aim with her pistol. Taro must have been virtually lying on the sand for the shot, and she captures a powerful combination of vulnerability, beauty and determination. By the end of her career her work had gained an intensity of meaning and a weight of psychological truth. She was easily as good as Capa.

Many of Capa’s negatives have been lost over the years, but what there is are here, including the superb shot of a Chinese boy soldier taken in 1938, which appeared on the cover of Life.

Of the contemporary artists, Geert van Kesteren’s Iraq work stands out, as do An-My Lê’s photographs. The contrast with Capa and Taro shines a spotlight on how photographers still deal with the spectacle of war.

— This is War! Robert Capa at Work and Gerda Taro: On the Subject of War are at the Barbican from Friday until Jan 25

Editor's choice

• U2 at Nou Camp Stadium, Barcelona
• The 50 Best Movie Villains
• The 15 golden rules of theatre etiquette