Sigma has introduced its shortest focal length zoom lens for digital SLR cameras to date in the form of the 8-16mm f/4.5-5.6 DC HSM. Designed for use on APS-C format cameras, the lens appears equivalent to a 12-24mm optic on 35mm format and has a wideangle view of 121.2 degrees. Like two other of the five new and updated lenses announced, the 8-16mm DC HSM, features elements made from Sigma?s new FLD (?F? Low Dispersion) glass for reduced dispersion and aberration correction. The lens has 15 elements in 11 groups with four FLD elements, one hybrid aspherical lens and two glass-moulded elements that correct for distortion and astigmatism. With minimum focus of 24cm, the 8-16mm optic measures 75×105.7mm and weighs 545g.
Sigma has also introduced the 17-50mm f/2.8 EX DC OS HSM, a stabilised lens for APS-C format cameras, with a standard-zoom focal length equivalent to 25.5-75mm. Sigma claims the Optical Stabilizer extends the safe hand-holdable shutter speed by up to 4 stops. The lens is constructed from 17 elements in 13 groups, with two FLD glass elements, plus two glass elements and one hybrid aspherical lens. It has a minimum focusing distance of 28cm and dimensions of 83.5×91.8mm.
The third new lens is an 85mm f/1.4 EX DG HSM, which is suitable for use on both full-frame and APS-C format DSLRs. This focal length is ideal for portrait photographers on either format, while the wide maximum aperture provides extensive control over depth of field. The lens has a rear focus system that reduces the variation in aberration caused by focussing. It measures 84.7×87.6mm and features 11 elements in 8 groups, with one SLD (Special Low Dispersion) glass element and one glass moulded element.
The two updated lenses, the 50-500mm f4.5-6.3 DG OS HSM and 70-200mm f/2.8 EX DG OS HSM introduce Sigma Optical Stabilizer system to existing lenses to extend the safe hand-holdable shutter speed by four stops. The 50-500mm f4.5-6.3 DG OS HSM has 22 elements in 16 groups with four SLD (Special Low Dispersion) glass elements for chromatic aberration correction, while the 70-200mm f/2.8 EX DG OS HSM has 22 elements in 17 groups with two FLD glass elements and three SLD elements. The 50-500mm lens measures 104.4x219mm and weighs 1,970g, and the 70-200mm is 86.4×197.6mm, with weight yet to be announced.
All the lenses feature Sigma?s HSM Hyper Sonic Motor that delivers quieter, faster AF along with full-time manual focus capability, while Super Multi-Layer Coatings reduce flare and ghosting. They will all be available in Canon, Nikon, Sigma, Sony and Pentax fit.
- 8-16mm f/4.5-5.6 DC HSM
- 17-50mm f/2.8 EX DC OS HSM
- 85mm f/1.4 EX DG HSM
- 70-200mm f/2.8 EX DG OS HSM
- 50-500mm f4.5-6.3 DG OS HSM
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Lens hood
The 70-200mm f/2.8 EX DG OS HSM and 85mm f/1.4 EX DG HSM are supplied with a hood adaptor, which is designed for use with APS-C format cameras. The adaptor is essentially a tube that moves the hood further out from the lens. Because the only the centre portion of the lens? image circle is used with smaller format cameras, the risk of vignetting is lower than with full-frame cameras so there is scope to extend the hood and provide extra protection for the centre of the lens
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F Low Dispersion
Sigma?s new 8-16mm f/4.5-5.6 DC HSM, 17-50mm f/2.8 EX DC OS HSM and
70-200mm f/2.8 EX DG OS HSM feature at least one element made from FLD (?F? Low Dispersion Glass). Sigma claims that this new glass, which has been developed jointly with Hoya, has the low dispersion and high light transmission properties of fluorite. Fluorite has a low refractive index and creates less dispersion and chromatic aberration than standard optical glass, but it is heavy and expensive. The new Sigma glass is claimed to have the same beneficial properties as fluorite, but it is more affordable and lighter.
