Compact, yet long-reaching, the 500mm f/8 HD Telephoto Mirror Lens from Opteka is a reflex lens featuring a threaded T-mount for adapting to a wide variety of camera types. The Cassegrain design enables it to achieve a 500mm focal length within a compact and lightweight form factor that is significantly smaller than a traditional 500mm lens. Its optical design is also fully multi-coated to suppress lens flare, ghosting, and surface reflections for increased contrast and color neutrality when working in strong lighting conditions. Manual focus control is possible down to 5.5' with a 1:2.7 maximum magnification ratio for working with close-up subjects, and the lens accepts both 72mm front and 30.5mm rear threaded filters. 30.5mm ND-2X, 30.5mm ND-4X, and 30.5mm skylight filters are included along with a lens pouch for travel or storage.