Image © Sigma Corporation

Sigma Corporation have today announced a raft of new lenses available in numerous digital SLR mounts. Among them is the Sigma 17-50mm F/2.8 EX DC OS HSM. This wide angle to traditional focal length zoom (FX format) has an impressive sounding optical make-up.

The fast maximum aperture,  two FLD low dispersion elements, the lens also features an anti-shake stabalisation (OS) function, up to a claimed 4 stops equivalent. Autofocus is controlled by a built in HSM motor, while the diaphram is designed to create a more pleasing out of focus background blur wiih a circular opening shape. The  fast aperture and other advanced features pit it against no clear direct Nikkor equivalent at present.

Here is the official press release from Sigma Corporation:


February 2010

17-50mm f2.8 EX DC OS HSM Compact large aperture standard zoom lens equipped with OS

The Sigma Corporation is pleased to announce the new Sigma 17-50mm F2.8 EX DC OS HSM.

This large aperture standard zoom lens is designed for digital SLR cameras and incorporates Sigma’s efficient OS function. It is a compact lens with an overall length of just 91.8mm (3.6”). This lens covers a focal length from 17mm wide angle and offers a large aperture of F2.8 throughout the entire zoom range, making it ideal for many types of photography such as portraiture and landscapes. The OS (Optical Stabiliser) function offers the use of shutter speeds approximately 4 stops slower than would otherwise be possible. For Sony and Pentax mount, the built-in OS function of this lens can be used even if the camera body is equipped with an image sensor shift anti-shake system. As compensation for camera shake is visible in the viewfinder, the photographer can easily check for accurate focus and ensure there is no subject movement.

Two FLD (“F” Low Dispersion) glass elements, which have performance equal to fluorite glass, plus two glass mold and one hybrid aspherical lens, provide excellent correction for all type of aberrations. The Super Multi-Layer Coating reduces flare and ghost. This lens has superior peripheral brightness and provides sharp, high contrast images even at the maximum apertures. High image quality is assured throughout the entire zoom range.

Incorporating HSM (Hyper Sonic Motor), the lens provides fast and quiet AF. The lens has a minimum focusing distance of 28cm (11”) throughout the entire zoom range and a maximum magnification ratio of 1:5. The rounded 7 blade diaphragm creates an attractive blur to the out of focus images. The inner focusing system eliminates front lens rotation, making the lens particularly suitable for use with the supplied petal-type lens hood and circular polarising filters.

* Vignetting will occur if the lens is used with digital cameras with image sensors larger than APS-C size or 35mm SLR cameras. * For Pentax and Sony mount, when the OS function of lens body is used, please turn the stabilizer function of camera body off. * It is not possible to use the built-in OS function and AF of this lens with Pentax ist *series and the K100D.


Minimum Aperture F22 Minimum Focusing Distance 28cm
Lens Construction 17 Elements in 13 Groups Maximum Magnification 1:5
Angle of View 72.4°- 27.9° Filter Size 77mm
No. of Diaphragm Blades 7 pcs Lens Hood Petal-type
Weight TBA SRP £899.99
Dimensions Diameter 83.5mm x Length 91.8mm
Available Fittings Sigma AF, Nikon AF, Canon AF, Pentax AF, Sony AF

End. (21/02/10).