Offered is a Mirror Universar Ultra-Telephoto 500mm f/8, a classic catadioptric (mirror) lens. This type of lens design uses a combination of mirrors and glass elements to fold the light path, allowing for a very long 500mm focal length in a remarkably compact and lightweight barrel compared to traditional refractive telephoto lenses. It is an ideal tool for specialized photography such as astrophotography, wildlife, and long-range surveillance. Mirror lenses are famous for their unique "donut-shaped" bokeh (out-of-focus highlights), which adds a distinctive creative character to images. Specifications Lens Type: Catadioptric (Mirror) Telephoto Lens Focal Length: 500mm Fixed Aperture: f/8 Focusing: Manual focus with a large, textured rubber grip Focusing Range: Scale marked in meters (m) and feet (ft), reaching from approximately 10m to infinity Mount: Likely T2 mount (standard for these lenses), adaptable to most SLR and mirrorless systems Construction: All-metal barrel with a black finish Condition Cosmetic: The lens is in excellent aesthetic condition with minimal signs of use. The black finish is clean and the distance scale markings are bright and legible. Mechanical: The focusing ring rotates smoothly across its entire range. Optical: The front glass and internal mirrors appear clear and well-preserved. Accessories: Includes the original brown cylindrical hardshell carrying case with a red velvet-style lining and a protective front lens cap. Please note: This is a manual focus lens with a fixed aperture. It has not been tested with a camera or film. The images are an integral part of the description.