Sigma 17-50mm f2.8 EX DC OS HSM

Sigma 17-50mm f2.8 EX DC OS HSM

The Sigma 17-50mm f2.8 EX DC OS HSM lens is an image-stabilised, fast standard zoom for digital SLR cameras with an APS-C sized sensor. The lens covers a focal length from 17mm wide angle and offers a large aperture of f/2.8 throughout the entire zoom range, making it ideal for many types of photography such as portraiture and landscapes. Alongside Sigma's Optical Stabilizer (offers the use of shutter speeds approximately 4 stops slower than would otherwise be possible), the 17-50mm OS lens also includes a hypersonic autofocus motor, for quicker, quieter focusing. It uses two elements made from Sigma's new FLD glass, plus two glass mould and one hybrid aspherical elements, to reduce aberrations and offer excellent image quality. Super Multi-Layer Coating reduces flare and ghost, meaning the Sigma 17-50mm lens has superior peripheral brightness and provides sharp, high contrast images even at the maximum aperture.

Sigma 17-50mm f2.8 EX DC OS HSM - Key Features

FLD ("F" Low Dispersion) glass elements

Two FLD ("F" Low Dispersion) glass elements, which have the performance equal to fluorite glass, compensate for color 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.

*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.

Sigma's own unique OS (Optical Stabilizer) technology

The lens is equipped with Sigma's own unique OS (Optical Stabilizer) function. This system allows the photographer to use shutter speeds approximately 4 stops slower.

*Sony and Pentax mounts are not incorporated with OS function.
*For Pentax mount, if the camera body does not support HSM, auto focus will not be available.

F2.8 Large aperture throughout the entire zoom range

The large aperture 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 and allowing the use of fast shutter speeds.

Covering a wide range of focal lengths from 17mm

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 portraits, landscapes and general photography.

*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

The Super Multi-Layer Coating reduces flare and ghosting as well as providing sharp and high contrast images throughout the entire zoom range.

Superior peripheral brightness

This lens has superior peripheral brightness and provides sharp and high contrast images even at the maximum apertures.

Fast and quiet AF Hyper Sonic Motor

The lens incorporates HSM (Hyper Sonic motor), ensuring fast and quiet AF.

*For Pentax mount, if the camera body does not support HSM, auto focus will not be available.

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.

Inner focusing system

The inner focusing system eliminates front lens ration, making the lens particularly suitable for using the supplied petal-type hood and circular polarizing filters.

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

Lens Terminology

DC

Sigma’s DC lenses are designed for cameras with a cropped sensor. Do not put a Sigma DC lens on a camera with a full-frame sensor, such as the 5D Mark III. These are special lenses designed so that the image circle matches the smaller size of the image sensor of most digital SLR cameras. Their specialised design gives these lenses the ideal properties for digital cameras, the compact and lightweight construction is an added bonus.

HSM (Hyper-Sonic Motor)

This lens uses a motor driven by ultrasonic waves to provide a quiet, high speed AF.

EX

The exterior of this lens is EX-finished to denote the superior build and optical quality, and to enhance its appearance.

OS (Optical Stabilizer)

This function utilises a built-in mechanism that compensates for camera shake. It dramatically expands photographic possibilities by alleviating camera movement when shooting hand held.