Sigma Corporation has announced the release of its new 17-50mm f/2.8 EX DC OS HSM lens. The lens is designed for digital cameras with an APS-C sensor. It incorporates Sigma's Optical Stabilization (OS) functionality and new FLD glass. The lens is small, with an overall length of 3.6 inches, and has a large, fast maximum aperture. Its minimum focusing distance is 11 inches throughout the entire zoom range and its maximum magnification ratio is 1:5.
Sigma claims that the OS function permits the use of shutter speeds approximately four aperture stops slower than what would otherwise be possible. Users of Pentax and Sony cameras, which have image stabilization systems built into the camera body, have the option of using their cameras' image stabilization system or the system offered by the new Sigma lens.
Sigma's FLD glass, which is used in the new lens, has high light transmission and anomalous dispersion. It offers correction for residual chromatic aberration, which cannot be corrected by ordinary optical glass, and Sigma claims that it ensures high definition and high contrast images.
Sigma's new lens is a hybrid aspherical lens made with two glass mold elements for correction of distortion and astigmatism. It has a multi-layer coating to reduce flare and ghosting and Sigma's Hyper Sonic motor to provide quiet and high-speed auto focus. The lens' rounded, seven-blade diaphragm creates an attractive blur to out-of-focus areas and its inner focusing system eliminates front lens rotation, making the lens particularly suitable for use with the supplied petal-type lens hood and circular polarizing filters.
The lens is currently available for Canon cameras at a list price of $980, and will be available for Nikon, Sigma, Sony and Pentax cameras in the coming weeks. For additional information about this new lens, see Sigma's website.