focusring

Focus ring refers to a control used to adjust focus on a camera lens, or to a visual indicator used in digital interfaces to show which element has keyboard focus.

In optical equipment, the focus ring is a textured ring on the lens that the photographer rotates to change the lens' focal distance. As the ring turns, lens elements move relative to the sensor, changing the point at which light is brought into sharp focus. On many lenses there is tactile feedback, with a finite rotation angle. Some modern systems use focus-by-wire: rotating the ring sends an electronic signal to a motor, and there may be no direct mechanical coupling.

In digital user interfaces, a focus ring is the visible outline around the currently focused interactive element. It appears when using a keyboard, tab, or other non-pointer input. Accessibility guidelines recommend keeping a high-contrast focus ring or customizing it with CSS to ensure visibility. The recommended practice is to use the focus-visible pseudo-class to show the ring primarily for keyboard users, while avoiding decorative rings for mouse users.

Variants and interaction: In photography, working with a focus ring requires careful handling to maintain critical sharpness, especially in manual focus, macro, or video. In software, developers can style the focus ring via CSS and ensure it remains readable against the element’s background. Focus rings are an important aspect of both photographic technique and accessible UI design.