What is the primary idea behind using selective focus in a shot?

Using selective focus in a shot serves primarily to enhance the emotional impact by drawing the viewer's attention to a specific area, often highlighting an important character or detail within the frame. This technique can guide the audience’s focus, emphasizing feelings, thoughts, or themes presented in that particular moment of the narrative.

By blurring backgrounds or other elements, the filmmaker can create a sense of intimacy or urgency, allowing viewers to connect more deeply with the subject in focus, often reflecting their emotional state or significance in the scene. This selective attention encourages viewers to engage with the film on a more personal level.

Other choices, such as bringing everything into focus or creating confusion, do not align with the purpose of selective focus, which is about clarity and intention rather than ambiguity. Additionally, introducing multiple characters at once does not correspond with the concept of selective focus, which typically aims to concentrate on a singular point to convey deeper meaning.