Sigma 28-105mm F2.8 sets what could be a new standard for standard zoom lenses

Sigma has launched a new full-frame standard zoom lens with a constant f/2.8 aperture. But where most f/2.8 standard zooms have a 24-70mm focal length, the new Sigma ups the ante by offering a 28-105mm focal range.

The Sigma 28-105mm F2.8 DG DN | Art has been designed for a wide range of subjects, from landscapes to all forms of portraiture, and even close-up shots, thanks to a 40cm minimum focus distance available throughout the focal range. That large maximum aperture also means low light needn't be an issue, and Sigma is claiming the 12-blade rounded diaphragm produces "beautiful" bokeh.

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Inside is an 18-element optical stack incorporating 2 FLD (“F” Low Dispersion), 1 SLD (Special Low Dispersion) and a whopping five aspherical elements. Sigma also states that one aspherical element is an especially large 66.4mm diameter and is therefore very difficult to produce, requiring advanced manufacturing techniques in Sigma's facility in Aizu, Japan. Nano Porous Coating and Super Multi-Layer Coating are applied to minimize flare and ghosting, and the lens is said to have been designed using advanced simulation technology to further reduce flare and ghosting.

This isn't the first time we've seen a constant f/2.8 standard zoom lens that goes longer than 70mm. Canon's RF 24-105mm F2.8L IS USM Z manages a similar feat, but the new Sigma is significantly smaller and lighter. Where the big Canon measures 88.5 x 199mm and weighs a hefty 1,430g, the Sigma is just 87.8 x 157.9mm, and around a third lighter at 995g. This weight reduction is thanks to the use of magnesium-alloy rather than aluminium for the lens barrel, which is responsible for a two-third reduction in barrel weight, while still maintaining good rigidity. Despite the weight-saving, the lens is fitted with weather seals, making it dust and splash-resistant, while the front element features a water- and oil-repellent coating. In addition to improving image quality, those five aspherical elements also help reduce the overall length of the lens without compromising optical sharpness.

Like its Canon 24-105mm counterpart, the Sigma 28-105mm F2.8 DG DN | Art is designed for both stills and video use. It incorporates an HLA (High-response Linear Actuator) autofocus motor for fast, responsive, precise and smooth AF, along with "noise-free" performance when shooting video. Also aiding video use is a dedicated aperture ring, equipped with a de-click switch, as well as a locking switch to prevent unintentional aperture adjustment. The zoom ring can also be locked, and released either by switch or by rotating the zoom ring.

The SIGMA 28-105mm F2.8 DG DN | Art will be available from September 26 , in Sony E-mount and L-Mount variants, priced at $1,499/£1,399.