Rokinon 500mm Mirror Lens for Nikon Mount + 2X Teleconverter Lens [Camera] Aperture: F8.0 Fixed Optical Construction: 7 Elements in 6 Groups Angle of View: 5 Degrees; Minimum Focusing Distance: 1.70m (5.6ft) Filter Size: Rear = 30.5mm, Front = 72mm Focus Type: Manual; Mount: T-Mount Adapter (Included for Nikon Mount) Includes: 2X Teleconverter Lens