Autofocus systems are technologies used in cameras to automatically adjust the lens to achieve a sharp image. They work by detecting contrast or phase differences in the light coming through the lens, allowing the camera to focus on the subject quickly and accurately. Common types of autofocus systems include contrast detection and phase detection. These systems are essential for both photography and videography, as they help capture clear images without manual adjustments. Many modern cameras, including DSLRs and mirrorless cameras, feature advanced autofocus systems that can track moving subjects and perform well in low-light conditions.