The dedicated 1.4x APO Tele-converter features a high performance 5 element-3 group optical design and it is optimized for use with long telephoto and tele-zoom lenses. The high performance optical characteristics of these tele-converters maintain the optical performance of the compatible lenses with which they can be used. Using 10-pin electrical interfaces there is no loss of auto focusing speed when these tele-converters are used with compatible H.S.M. type lenses for Canon Sigma and now current Nikon AF cameras, except N60-F60 models. They are ideally suited for use with the 70-200mm F2.8 APO EX HSM zoom lens providing normal exposure and auto focus function while maintaining its high optical performance.