Please combine the history of battlefield photography development and analyze the characteristics of documentary photography development.

This problem covers a long time. In my impression, there are no special works in mainland China at present. Let me briefly say a few things I know: the earliest battlefield photography appeared during the American Civil War, using a wet version (? The problem of shooting and posing exists, and the requirements for politics and art are much higher than those for documentaries. About 100 sets of base plates. Next, although the war continues, the development of battlefield photography has not made much progress. During the First World War, more battlefield photography appeared. The most important battlefield photography appeared during the Second World War, represented by robert capa. He wrote an autobiography, Out of Focus, which was published by Guangxi Normal University Press. Opened the documentary style of battlefield photography. His philosophy is to keep getting closer. But in the end, because I was too close, I died in the Vietnam War battlefield, haha.