Feature:1. Super Telephoto Zoom Lens: The lens features manual focusing in F/8.3-16 aperture at 420-800mm focal length, to separately control the super focal zoom from DSLR SLR cameras.2. Fit for AI Mount Camerat: T mount lens with adapter ring, replacement for T/T2 lenses to AI mount D50 D90 D5100 D7000 D3 D5100 D3100 D3000 D60 and more cameras.3. 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 sturdy constructions.4. Ultra Multi Coating: Adopts multi coated technology to reduce flare and ghost to get vivid color and clear images. Premium optical lens provides high light transmittance.5. 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.Specification:Specifications:Material: MetalMount: T2 mountReplacement for: for AI mount D50 D90 D5100 D7000 D3 D5100 D3100 D3000 D60 camerasFocal Length: 420-800mm zoom lensAperture: f/8.3@420mm-f/16@800mmOptical Constructions: 4 elements in 2 groupsZoom System: Linear push-pullExposure: Automatic exposure is available in Aperture Priority mode only for cameras with TTL metering systems; Other camera must be set in full manualFocusing: Manual helical (rotating) operating(Not AF compatible)Minimum Focusing Distance: 1.6 meters(5.25ft) from front lensFilter Size: 67mmDiameter: 69mmLength: 24-35cm / 9.45-13.38in(with caps)Lens Dimension: 24 * 7 * 7cm / 9.45 * 2.76 * 2.76inAdapter Ring Dimension: 6 * 6 * 1.3cm / 2.36 * 2.36 * 0.51inWeight: 659g / 18.3oz.Package List:1 * MF Super Telephoto Zoom Lens1 * Adapter Ring1 * Front Cap1 * Rear Cap1 * Carrying Pouch