Sigma has announced ten new zoom lenses, including what the company claims to be ?the world’s first lens to offer an f/2.8 aperture at 500mm?.

The announcements expand the company?s Four Thirds portfolio, as well as catering for both full-frame and APS-C sized sensors.

The APO 120-400mm f/4.5-5.6 DG OS HSM and APO 150-500mm f/5-6.3 DG OS HSM both feature Optical Stabilisation and Hypersonic Motor technology, and each feature three Super Low Dispersion (SLD) elements. Both lenses will be available in Sigma, Canon, Nikon, Pentax and Sony mounts, and may be used with Sigma?s APO teleconverters to extend their effective focal lengths.

Two models have also been announced for the Four Thirds mount. The 10-20mm F4-5.6 EX DC HSM and APO 70-200mm F2.8 II EX DG MACRO HSM boasts three and two SLD elements respectively, with the former also featuring three aspherical elements. Both lenses also feature Super Multi Coating and Hypersonic Motors.

Two further lenses have been announced for Pentax and Sony users: the APO 70-200mm F2.8 II EX DG MACRO and APO 50-150mm F2.8 II EX DC HSM. Both lenses feature a constant f/2.8 aperture and Hypersonic Motors and, as with the above three APO lenses, offer compatibility with Sigma?s 1.4x and 2x teleconverters.

The optically-stabilised 18-125mm f/3.8-5.6 DC OS HSM lens, meanwhile, boasts SLD glass and Aspherical elements and will be available in Sigma, Canon, Nikon, Pentax and Sony mounts. A further two lenses, the 70-300mm f/4-5.6 HSM and the APO 70-300mm f/4-5.6 HSM, have been designed with Nikon D40, D40x and soon-to-be D60 users in mind. Their built-in motors make autofocusing possible when used with the above bodies, with the APO lens compatible with Sigma APO teleconverters.

The icing on Sigma?s cake, however, is the 200-500 f/2.8 EX DG lens. WDC Editor Nigel Atherton was pictured last year with a prototype of the lens (see right), though it appears to have now undergone a cosmetic makeover, now sporting a distinctive green barrel. Weighing a whopping 15.7kg, the lens needs its own lithium battery to aid focusing and zooming, with an LCD screen displaying shooting information. SLD glass and three Extra Low Dispersion (ELD) elements help make up the lens’s internal construction, with an optional attachment available to reach focal lengths of 400-1000mm.