What is the key feature of deep focus in cinematography?

Deep focus in cinematography is characterized by the ability to have everything in the frame, including both the background and foreground, in sharp focus. This technique allows viewers to engage with multiple elements of a scene simultaneously, providing a more immersive experience. It encourages the audience to explore the entire composition, as significant action or detail may occur in different planes of the image.

This is particularly effective in storytelling as it can convey the relationship between characters and their environment, enhancing narrative depth. Directors like Orson Welles famously employed deep focus in films such as "Citizen Kane," where it serves to create complex visual storytelling, allowing viewers to gather more contextual information from the entire frame rather than focusing solely on a single subject.

In contrast, the other options emphasize selective focus, which can restrict viewer engagement to a only one part of a scene rather than allowing for a comprehensive understanding of the spatial relationships within the frame.