Sigma's has been known the world over for their innovative design, ease of use and for the excellent results that their zoom lenses produce - this offering is no exception.
The new 70-200mm f2.8 EX APO IF lens features an apochromatic optical design and four elements composed of Special Low Dispersion (SLD) glass for high image contrast, resolution and color saturation.
For optimum performance in just about any photographic situation, an internal focusing system means that the front barrel does not rotate during focusing.
For stability and the use of specialty filters, This internal focusing system is a must.
The internal zooming mechanism allows the lens length to remain constant during zooming.
The Focus Free mechanism keeps the manual focus ring from spinning when the camera is auto-focusing.
The 70-200mm f2.8 EX APO IF is fully compatible with both the Sigma AF 1.4X and 2X APO EX Tele-converters.
The new 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 new dedicated 2x APO Tele-converter features a 6 element/5 group optical design, and it is specifically designed for use with longer 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 and Nikon AF SLR cameras.
They are ideally suited for use with the 70-200mm F2.8 APO EX HSM zoom lens; providing normal exposure and autofocus function, while maintaining its high optical performance.''An exceptionally easy-to-use, pro-quality, constant-aperture tele-zoom lens with good close-focus optical quality.'' Popular Photography, August 1998
