The key criteria of documentary photography are

Documentary photography shows the photographer's concern for the environment, respect for life, and pursuit of humanity ... Documentary photographers use cold machines to record marginal scenes or facts that are intentionally or unintentionally "ignored", but they can often use the power of images to make photography a tool to participate in social transformation. Judging from the social background and historical absence of documentary photography, its criticism and revolution are self-evident. By-product documentary photography history is the history of injustice, darkness, turbulence and austerity in the world that photographers record, express and spread. They use images to achieve the purpose of propaganda and agitation, and then promote social change and make the world a better place. These are the characteristics and functions of Jishi photography.