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. There are different types of autofocus systems, including contrast detection and phase detection. Contrast detection measures the sharpness of the image, while phase detection uses a dedicated sensor to determine the focus distance. Many modern cameras, including DSLRs and mirrorless cameras, utilize these systems to enhance photography and videography experiences.