A super telephoto focal length with a relatively tiny form factor, the 500mm f/6.3 Mirror Lens from Opteka is a reflex lens featuring a threaded T-mount for adapting to a wide variety of camera types. Its 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 6.6' for working with close-up subjects, and the lens accepts both 95mm front and 34mm rear threaded filters.