Product description

17-50mm f/2.8 EX DC OS HSM

Large aperture standard zoom lens with a minimum focal length of 17mm, designed exclusively for digital SLR cameras and incorporating Sigma's original Optical Stabiliser system.

The OS function offers the use of shutter speeds approximately 4 stops slower than would otherwise be possible. The lens has a compact construction with an overall length of 91.8mm making it ideal for travel photography. Two FLD ("F" Low Dispersion) glass elements, two glass mold and one hybrid aspherical lens provide excellent correction for all types of aberrations. This lens has superior peripheral brightness and provides sharp and high contrast images even at the maximum apertures. The incorporation of HSM (Hyper Sonic Motor) provides fast and quiet AF.

FLD ("F" Low Dispersion) glass elements
FLD glass is the highest level low dispersion glass available with extremely high light transmission. This optical glass has a performance equal to fluorite glass which has a low refractive index and low dispersion compared to current optical glass. It also benefits from high anomalous dispersion. These characteristics give excellent correction for residual chromatic aberration (secondary spectrum) which cannot be corrected by ordinary optical glass and ensures high definition and high contrast images.

This lens incorporates two FLD glass elements, which compensate for colour aberration. In addition, two glass mold elements and one hybrid aspherical lens give excellent correction for field curvature and astigmatism. High definition images are ensured throughout the entire zoom range .

Sigma's unique Optical Stabiliser technology
The lens is equipped with Sigma's own unique OS function. This system allows the photographer to use shutter speeds approximately 4 stops slower that would otherwise be possible.

Large aperture throughout the entire zoom range
The large F2.8 aperture allows the use of fast shutter speeds and provides a bright viewfinder image, helping the photographer confirm accurate focusing. It is also ideal for emphasizing the subject by creating a natural, blurred background.

Covering a wide range of focal lengths
This lens covers a wide range of focal lengths from 17mm and has an equivalent angle of view of a 25.5-75mm with a 35mm SLR camera. It is ideal for general photography as well as portraits and landscapes.
* The angle of view varies depending on which camera the lens is mounted on.

Compact construction
The lens has a compact construction with a diameter of 83.5mm, overall length of 91.8mm and weight of 565g. This compact and lightweight construction makes it ideal for travel photography.

Super Multi-Layer Coating and superior peripheral brightness
The Super Multi-Layer Coating reduces flare and ghosting as well as providing sharp and high contrast images throughout the entire zoom range. This lens also benefits from superior peripheral brightness and provides sharp and high contrast images even at the maximum apertures.

Fast and quiet AF with internal focusing
The lens incorporates HSM (Hyper Sonic motor), ensuring fast and quiet AF. The inner focusing system eliminates front lens ration, making the lens particularly suitable for using the supplied petal-type hood and circular polarising filters.
* For Pentax mount, AF will not function with DSLR cameras that do not support HSM.

Close focusing capability
This lens has a minimum focusing distance of 28cm throughout the entire zoom range and a maximum magnification ratio of 1:5.

Rounded diaphragm
This lens has rounded 7 blade diaphragm which creates an attractive bokeh to the out of focus area of the image.

* Vignetting will occur if the lens is used with digital cameras with image sensors larger than APS-C size or 35mm SLR cameras.

Specifications.

Lens Construction 17 Elements in 13 Groups

Angle of View (SD Format) 72.4 - 27.9 degrees

Number of Diaphragm Blades 7 Blades (Rounded diaphragm)

Minimum Aperture F22

Minimum Focusing Distance 28cm

Maximum Magnification 1:5

Filter Size 77mm

Dimensions Diameter 83.5mm X Length 92mm

Weight 565g