A viewfinder is an optical device used in cameras and other imaging equipment to help users frame and compose their shots. It provides a preview of what the camera will capture, allowing photographers to see the scene before taking a picture. Viewfinders can be optical, using lenses and mirrors, or electronic, displaying a digital image on a screen. In addition to cameras, viewfinders are also found in devices like binoculars and telescopes. They enhance the user experience by providing a clear line of sight and helping to stabilize the image, making it easier to focus on the subject being observed.