F/8.3-16 aperture at 420-800mm focal length, to separately control the super focal zoom from cameras. T-Mount Lens to AI-mount: T mount lens with adapter ring, replacement for T/T2 lenses to Nikon AI-mount D50 D90 D5100 D7000 D3 D5100 D3100 D3000 D60 cameras. Functional Structure: The lens consists of 4 elements in 2 groups, with lock to fix the lens for precise shoot. Whole metal structured body provides with tough and durable constructions. Ultra Multi Coating: Adopts multi-coated technology to reduce flare and ghost to get vivid color and clear images. Premium optical glass lens provides high light transmittance. Universal 1/4 Mounting: The base with 1/4 screw thread down the lens makes wide application on tripod and monopod, the base with ring can rotate, convenient to install in seconds. Specifications: Color: Black/ White(optional) Material: Metal Mount: T2 mount Adapter Ring Mount: T2-AI Replacement for: Nikon AI-mount D50 D90 D5100 D7000 D3 D5100 D3100 D3000 D60 cameras Focal Length: 420-800mm zoom lens Aperture: f/8.3 #64;420mm-f/16 #64;800mm Optical Constructions: 4 elements in 2 groups Zoom System: Linear push-pull Exposure: Automatic exposure is available in Aperture Priority mode only for cameras with TTL metering systems; Other camera must be set in full manual Focusing: Manual helical(rotary) operation(Not AF compatible) Minimum Focusing Distance: 1.6 meters(5.25ft) from front lens element Filter Size: 62mm Diameter: 69mm Length: 24-35cm / 9.45-13.38in(with caps) Lens Dimension: 24 * 7 * 7cm / 9.45 * 2.76 * 2.76in Adapter Ring Dimension: 6 * 6 * 1.3cm / 2.36 * 2.36 * 0.51in Weight: 659g / 18.3oz Packing List: 1 * MF Super Telephoto Zoom Lens 1 * T2-AI Adapter Ring 1 * Front Cap 1 * Rear Cap 1 * Carrying Pouch