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Sigma 18-50mm EX DC OS HSM review

Zoom Lens Upgrades

Our Verdict

An excellent lens, and cheaper than the Sony lens we tested

For

  • Fast f/2.8 constant-aperture

Against

  • Colour fringing can be slightly noticeable towards the edges of the frame

It's not often that an independently manufactured lens costs more than some camera manufacturers' own-brand rivals, but this Sigma is a bit special. Unlike the Canon and Nikon lenses on test, the Sigma 17-50mm boasts a fast, constant aperture of f/2.8 that remains fixed throughout the zoom range.

That's quite an achievement for a lens that also includes optical image stabilisation. Other finery includes two of Sigma's FLD glass elements, which the company claims provides the very best low-dispersion performance to reduce chromatic aberration while enabling maximum light transmission.

Performance

The HSM (HyperSonic Motor) autofocus system fitted to this lens isn't Sigma's best, because there's no full-time manual override. Unlike many Sigma HSM lenses, the focus ring rotates during autofocus, so you have to be careful not to foul the action of the focus ring in handheld shooting.

A drawback of many fast lenses is that images lack a little sharpness and contrast when shooting at the maximum aperture, but the Sigma proved amazingly crisp at f/2.8 throughout.

Distortion is well controlled, and while there's a little colour fringing, it's only really noticeable around very high-contrast edges. There's also a distinct lack of vignetting, with excellent peripheral illumination in the corners of even wide-angle images.

Tech Focus…

The optical stabiliser works well with most Pentax and Sony bodies, but you need to turn off the camera's own sensor-shift stabiliser to avoid the two systems conflicting with each other.

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Tech Specs

Product TypeLens
Maximum Focal Length50 mm
Minimum Focal Length18 mm
Lens Mount TypeNikon F
Maximum Aperture Fixed2.8
Optical Zoom2.7x
Brand NameSigma
Filter Attachment Diameter72 mm
Lens TypeZoom
Application/UsageCamera
Minimum Focus Distance300 mm
Minimum Aperture22
Diameter79 mm
Depth85.8 mm
Compatibility

Nikon DSLR Cameras

Magnification0.33x
ManufacturerSigma Corporation
Product Model580-944
Product Name580-944 Lens
Manufacturer Part Number580944
Manufacturer Website Addresshttp://www.sigma-imaging-uk.com
Marketing Information

Sigma's 18-50mm F2.8 EX DC Macro large-aperture f2.8 enables fast and accurate auto focusing in this standard zoom lens for digital cameras which is perfect for professional photographer or serious amateur photographer. When you need to stand ready for any photo opportunity you need a fast aperture so you can shoot in low existing light or at maximum range with a flash this Sigma macro lens is perfect. With its compact size and light weight, it's a necessary addition to your camera bag.

Weight (Approximate)450 g