What is the unique essential feature of photography?

the represented object must actually exist.

The characteristic of photography art is that the object it represents must be real. Genre is divided into news photography, portrait photography, landscape photography, still life photography and so on. The content of the photographed image can be divided into landscape photos, still life photos, portrait photos, custom photos, news photos and so on. The logic of photography lies in expressing the diversity of existence. The creator chooses a special way to show us some possibility of his own existence and gain poetic meaning where rational logic is meaningless.