* Fashion photography: Penn began his career as a fashion photographer, and he continued to work in the fashion industry throughout his life. His fashion photography is characterized by its elegant simplicity and its focus on the clothing rather than the model.
* Portraiture: Penn was also a master of portraiture, and he photographed a wide range of people, from celebrities and politicians to ordinary people. His portraits are known for their intimacy and their ability to capture the essence of the subject.
* Documentary photography: Penn also did some documentary photography, and he was particularly interested in documenting the lives of indigenous peoples. His documentary photographs are often characterized by their empathy and their respect for the subjects.
* Modernism: Penn was influenced by the modernist movement in art, and his work is characterized by its simplicity, its use of geometric forms, and its focus on the formal qualities of the image.