The Nikon TC-20E III 2x Teleconverter is an exceptional teleconverter optimised for use with FX and DX digital SLR cameras. It doubles the focal length of compatible Nikkor lenses. The TC-20E III is constructed of 7 elements in 5 groups and with Nikon’s Integrated Coating (IC) you will see improved colour and reduced flare. It has one aspherical lens element which virtually eliminates lens aberrations.
The 2x extender (also known as a teleconverter) will double the focal length of your existing lens, and will cut back the amount of light by 2 f-stops. For example, using this teleconverter with a 300mm lens will effectively increase the focal length to 600mm. A lens set to f/2.8 will now be f/5.6. Teleconverters are best used with longer telephoto lenses and are not recommended for lenses wider than 50mm, e.g. 28-105mm (35mm format).
The Nikon TC-20EIII Teleconverter also features an Aspherical Lens Element inside the Teleconverter that virtually eliminates coma and other aberrations, especially at wide apertures. While the Nikon Integrated Coating (IC) the lens elements enhances light transmission efficiency, improves colour consistency and reduces flare providing the user with crystal clear vibrant images.