Rokinon 500mm Mirror Lens for Sony Alpha Mount + 2X Teleconverter Lens 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 Sony Alpha Mount) Includes: 2X Teleconverter Lens