LONDON (Reuters) - It is one of the most famous yet controversial war photographs of all time.
Now an exhibition in London of photographer Robert Capa's work sheds new light on his picture of a Spanish Civil War militiaman at the moment he is shot dead.
"The Falling Soldier" picture taken on the Cordoba front in 1936 shows the white-shirted militiaman reeling backwards, his arm flung out as he drops his rifle.
It brought instant fame to the Hungarian-born Capa and came to symbolise the struggle against Fascism.
But over the years, questions have been raised over its veracity, with some suggesting it was staged. Capa himself gave few clues about the actual circumstances in which it was taken.
The exhibition at the Barbican Center, called "This is War -- Robert Capa at Work," gathers all the known images taken by Capa that day in September 1936 and by his companion Gerda Taro.
It also features more of his work in Spain, pictures from the Sino-Japanese War in 1938 and U.S. troops landing on the Normandy beaches on D-Day in 1944, as well as original magazines and Capa's own notes and letters.
The collection was curated by Capa biographer Richard Whelan, who died last year. Whelan had set out to answer the skeptics about "The Falling Soldier," Kate Bush, Head of Galleries for the Barbican, told Reuters.
"He went back to the archives and he found a lot more negatives of this particular moment. He unearthed more material that has helped conceptualize the falling soldier image."
Whether or not the picture was posed was notably raised by Phillip Knightley in his 1975 book on war correspondents "The First Casualty."
He quoted a reporter, O.D. Gallagher, who said Capa had told him it was staged when they shared a hotel room in Spain. Whelan believed that account was false.
The captions of magazines which ran the picture at the time stated the incident occurred during a Republican assault, first in the French magazine Vu in September 1936 then in U.S. magazine Life in July 1937.
"Robert Capa's camera catches a Spanish soldier the instant he is dropped by a bullet in his head in front of Cordoba," Life said -- the caption writer apparently mistaking the soldier's cap tassel for a shard of exploding skull.
The truth may lie somewhere in between, it seems.
The 40 frames were gathered from negatives from cut-up contact sheets. They show a group of militiamen, including the later victim, on a hill near Cerro Muriano lining up for the camera, leaping over a gully, and taking aim with their rifles.
But, Bush said, these shots do appear to be posed.
"This isn't the heat of battle, it is not a moment when they are under attack. They are taken in a way that suggests they are playing to the camera to some degree," she said.
The theory is that during this activity a rebel sniper picked off a militiaman, believed to be one Federico Borrell Garcia, right in front of Capa's Leica lens.
"The picture is obviously of someone dying. You couldn't possibly act that pose," Bush said.
A second soldier was also photographed as he was shot.
The Spanish Civil War could be seen as the first media war, Bush said. The writers and artists who flocked to Spain wanted their work to support the cause -- Capa among them.
"The moral and political issues were much clearer cut. The majority of people felt they were on one side and it was easy to make the judgment call about what was right and wrong."
If "The Falling Soldier" is Capa's most renowned work, many other photographs testify to his courage and compassion.
He visited China in 1938 under the auspices of Nationalist leader Chiang Kai-shek, whose troops were fighting invading Japanese forces. China was seen as the eastern front in the international battle against Fascism as Spain was in the West.
Photos depict a Japanese air raid over Hankou watched by anxious citizens. A poignant image is of the corpse of a boy shot by Japanese troops as he chased after his pig and hens.
As well as the stunning D-Day pictures of soldiers wading ashore under German fire -- later mirrored by director Steven Spielberg in the movie "Saving Private Ryan" -- the exhibition shows another chilling moment of death.
Accompanying U.S. troops into Leipzig in 1945, Capa photographed two soldiers manning a machinegun on a balcony.
A German sniper then hit one of them in the head. The next shots show a pool of blood spreading across the floor.
Capa, who was killed in Vietnam aged just 40, famously said: "If your pictures aren't good enough, you're not close enough."
But in a letter from China to his friend Peter Koester, he shows the dilemma behind the bravado. "The war photographer's most fervent wish is unemployment," he wrote.
Editing by Janet Lawrence