AF lock (AF-L) is a camera feature that allows you to lock focus on a predetermined point, ensuring the subject remains sharply focused even if it moves or if other elements in the scene might interfere with autofocus. This is particularly useful for fast-moving subjects, shooting through glass or fences, or capturing images in crowded or complex environments. By locking focus, photographers can recompose the shot without changing the focal point, improving accuracy and consistency in action, wildlife, sports, or street photography. AF-L helps achieve professional-quality sharpness in challenging focusing situations.