What aspect does an extreme close-up focus on?

An extreme close-up focuses on a very specific feature of the subject, such as an eye, a mouth, or a hand. This technique is often used in film, photography, and visual arts to create intimacy and convey emotion by isolating a particular detail that might otherwise be overlooked in a wider shot. By concentrating on a single element, the viewer is invited to engage more deeply with the subject's expression or action, enhancing the storytelling or thematic impact. This focus can evoke strong emotional responses, as it highlights nuances that contribute to the overall narrative.

The other options encompass broader areas of focus: the entire head, head and shoulders, or the full upper body, which do not fulfill the definition of an extreme close-up.