Sigma announced four new zoom lenses at PMA 2010, three of which use "F" low dispersion (FLD) elements, which the firm holds to perform as well as fluorite in compensating for colour aberration. The lower density optical material also results in a slight weight reduction.

The new 8-16mm F4.5-5.6 DC HSM, the first ultra wide zoom lens with a minimum focal length of 8mm, uses four FLD elements (a total 15 elements in 11 groups).

Casting an image circle only suitable for APS-C size image sensors, the compact lens offers an equivalent angle of view of a 12-24mm lens on a 35mm camera.
There's also one hybrid aspherical lens, and two glass mould elements; while Sigma's SuperMulti-Layer Coating reduces flare and ghosting.

The lens, equipped with Hyper Sonic Motor (HSM) full-time manual override capability, can focus to 24 cm throughout its zoom range.

Although pricing is TBA, expect April availability for Canon- and Nikon-compatible versions, says Gentec international, the Canadian distributor. Models with Pentax, Sigma, and Sony mounts are slated for later in the year. None of the lenses described here will come in the Four Thirds mount.

A new, compact walk-around lens, the Sigma 17-50mm F2.8 EX DC OS HSM, also benefits from Hyper Sonic focusing and FLD elements (two are employed here).

The f2.8 maximum aperture is maintained throughout its zoom range, while optical stabilization is said to deliver a four-stop advantage. For DSLRs with sensor-shift mechanical stabilization (Sony and Pentax), Sigma repeats its mantra that O.I.S. works via the viewfinder. Also. O.I.S. can outperform sensor shift in reducing camera shake in some situations.

Canadian availability is scheduled for June 2010 (for Canon and Nikon mounts).

While it's hardly compact (it casts a full-frame image circle), Sigma's APO 70-200 F2.8 EX DG OS HSM "pro-grade" zoom lens provides a large maximum aperture of f2.8 throughout its entire zoom range.

Two FLD elements (22 elements in 17 groups) and optical stabilization are on tap in a large, tri-pod mountable design. Expect this in May (Canon mount; with the other four to follow).

The massive (1,970 g) APO 50-500mm F4.5-6.3 DG OS HSM, a 10:1 zooming ultra telephoto design, is the only one of the four not to employ FLD glass; but you can find four Special Low Dispersion (SLD) glass elements among its 16 elements in 22 groups.

Also usable for full frame cameras, the big news is that this lens, an update of an existing formula, now benefits from optical stabilization. There's also Hyper Sonic Motor (HSM), and a maximum magnification ratio of 1:3.1 (at 200mm).

Availability is April for Canon and Nikon mounts.
For more information, visit: www.gentec-intl.com

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