This exercise demonstrates the result of varying focal length on a portrait, with progressively more distortion from wideangle (24mm), compared to standard focal length (50mm here), or medium/telephoto (70mm and 85mm). The longer focal lengths produce more attractive results. Elements of the face at wide angle are often out of proportion, whereas longer lenses have the effect of flattening features. While aperture will also be important, depth of field is reduced with a longer lens, so the background is thrown of out focus to a greater extent. The series below also illustrates that more of the background is included with a shorter lens (although note the barrelling, which is probably exaggerated by relatively wide aperture at f/4). While for a formal portrait this is unlikely to be desirable, wide angle lenses are used more commonly in reportage where inclusion of surroundings add context to the subject of the photograph.