Chairman Mao Zedong inspects troops at Xiyuan Airport in 1949 by Gao Fan.

Gao was a military photographer all his life, while Niu, who joined the PLA around 1947, moved to the Xinhua News Agency in the 1950s and remained there until her retirement in 1982.

Being a photojournalist enabled her to photograph a lot of people from the cultural and scholarly fields.

Among her photos are pictures of modern ink-brush masters at a national fine-arts exhibition in 1956.

There are also portraits of women from different walks of life, such as dancer Zhao Qing, painter-turned-social activist He Xiangning and farmers and workers.

One of her outstanding pictures is of mathematician Hua Luogeng (1910-85) looking at papers on a small table, lost in thought.

"When I took the photo of this famous professor in1956, I did not choose a regular way to portray this great scientist－piles of books and materials," says Niu.

Instead she chose a dark background to highlight Hua's slopping forehead and the drifting smoke from the cigarette in his hand.

"The composition is simple. But it is enough for people to feel the brilliance of this mathematician. Looking at his eyes and his thick spectacles, people can imagine how equations are processed in his mind," says Niu.

"Even decades after I took this photo, people who are familiar with Hua keep telling me that the photo captures his brilliance."

If you go

9 am-5 pm, through Sunday. 1 Wusi Dajie, Dongcheng district, Beijing. 010-6400-1476.