Features: 900mm F8.0 Telephoto mirror Lens, integrating the advantages of reflective-optic and refractive-optic, provides you with an extremely clear picture with minimum color abberation. Multi-coated and optuical glass element, wear-resistant, moisture-proof, anti-corrosion, pollution resistant and durable. Quality aluminum alloy body, solid in texture, exquisited in appearance and fine in workmanship. Large aperture of F8.0 greatly increases the amount of light entering, so as to obtain more reliable and safe shutter-time. Good choice for shooting sport activities, birds and wildlife as well as ultra-long distance photography. Specifications: Material: Magnesium Aluminum Alloy+Optical Glass+Multi-layer Coating Size: Standard Size Type: RF-mount, PK-bayonet, AF-bayonet, OM-bayonet, F-bayonet, E Mount, M4/3, XF-mount, KA-bayonet, EF-bayonet, EF-M Bayonet-mount(optional) Name: 900mm F8.0 Telephoto Mirror Lens Focal Length: 900mm Filter Size: 30.5mm(rear mount) Lens Construction: 8 Element in 8 Groups Focus-section: super distant fixed focusing Max-aperture: F8.0 Frame: full frame Closest Focusing Distance: 1.73m/5.7ft Focus-control: single-focus lens Angle of View: 3 Degree Lens Type: Manual Lens Lens: Multi-coated Anti-shake: no Length: 144.5mm/5.7" Max-diameter: 111mm/4.4" Package Includes: 1x 900mm F8.0 Telephoto Mirror Lens 1x Front & Rear Lens Covers 1x T2 Adapter Ring 1x Lens Pouch note: Please allow 0-1cm error due to manual measurement, make sure you do not mind before you order. Please allow slight chromatic aberration due to different display resolutions.