Official Sigma Press Release:
Sigma Corporation, a leading researcher, developer, manufacturer and service provider of some of the world's most impressive lines of lenses, cameras and flashes, is pleased to announce the release of its new 17-50mm F2.8 EX DC OS HSM lens. This large-aperture, standard-zoom lens, which was first introduced in February at Photo Marketing Association International, is designed for small chip, APS-C digital cameras and incorporates Sigma’s Optical Stabilization (OS) functionality and new, FLD glass. The 17-50mm F2.8 EX DC OS HSM is an ultra compact lens with an overall length of just 3.6 inches. The 17-50mm F2.8 EX DC OS HSM covers a focal length from a 17mm wide angle, has a minimum focusing distance of 11 inches throughout the entire zoom range and a maximum magnification ratio of 1:5. The lens is currently available in Canon mounts at all authorized Sigma dealers for the MSRP of $980, and it will be available in Nikon, Sigma, Sony and Pentax mounts in the coming weeks.
The OS function offers the use of shutter speeds approximately four stops slower than would otherwise be possible. Only Sigma has made it possible for Pentax and Sony shooters to utilize an anti-shake system in either the lens or the camera body. The compensation for camera shake is visible in the view finder for all mounts, which makes accurate focusing fast and easy.
“This lens is a must-have for any photo opportunity,” said Mark Amir-Hamzeh, general manager of Sigma Corporation of America. “The fast aperture allows for shooting in low, existing light or at maximum range with a flash. This is an ideal, all-purpose lens for everyday shooting.”
Sigma’s FLD glass, which is used in the new lens, has an extremely high light transmission and anomalous dispersion, making it the top level of low dispersion glass available. With a performance equal to fluorite glass, this optical glass has a low refractive index and low dispersion compared to current optical glass. These characteristics offer excellent correction for residual chromatic aberration (secondary spectrum), which cannot be corrected by ordinary optical glass and ensures high-definition and high-contrast images.
In addition, the 17-50mm F2.8 EX DC OS HSM also offers one hybrid aspherical lens and two glass mold elements for excellent correction of distortion and astigmatism. It has Super Multi-Layer Coating to reduce flare and ghosting with superior peripheral brightness and Hyper Sonic Motor (HSM) 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.
