A Fully Multi-Coated (Every Element) Low Dispersion Glass Capable Of Producing Sharp, High Definition Images <> Anti-reflection Coating High Speed Auto Exposure Capable <> Includes Deluxe Lens Case Infrared Compatible <> Compact and lightweight Aluminum alloy construction A T Mount Adapter Is Required To Attach This Lens (Sold Separately) The Polaroid 900mm f/8 Manual Focus Mirror Lens is an ultra-telephoto Mirror lens which, due to its mirror design, is incredibly compact and lightweight for its focal length. This is achieved by using an advanced reflex design. This lens is ideally suited for outdoor, sports, wildlife etc photography. It has a fixed aperture of f/8. This is a T-mount lens, which means that aperture is not communicated to or controlled by the camera body. There are T-mounts available from Polaroid for every DSLR system. Polaroid DNA is optics and lenses (as in Polarizing filters) , this Polaroid Lens is computer designed using a combination of lenticular light refraction and reflection optics - the same physics used in many professional telescopes. Combined with advanced manufacturing techniques and multi coated layers, the result is a lens with a sharp picture quality with less color aberration which is considered the most harmful factor in the field of telephoto photography. This lens is a highly complex, precision made optical instrument. Is has been individually assembled by skilled craftsman. With proper care and maintenance this lens will give you years of satisfying photographic results Specification: Angle Of View: 3 Degrees Minimum Focus Distance: 5.7' Magnification: 0.37x Elements/Groups: 8/8 Focal Length: 900mm Fixed Aperture: f/8 Coatings: Multi Filter Size Rear: 30.5mm Filter Size Front: 105mm Camera mount Type: T mount Length: 5 1/2" Weight: 640g Contents: Mirror Lens, Front and Rear Lens Caps, Lens case, Specification, Care And Use Sheet