(Sigma has organized its interchangeable lenses into three product lines: Contemporary, Art, and Sports. The Art line has been designed with an emphasis on artistic expression.)
As its name denotes, it features an optical stabilizer (OS) and Hyper Sonic Motor (HSM).
To compensate for the astigmatic aberration, field curvature, distortions, and colour aberration that standard lenses with a high zoom ratio tend to show, the new lens incorporates high-performance optics, such as FLD, SLD and glass-molded aspheric lenses. Chromatic aberration is suppressed effectively at the telephoto end, says the company, achieving superior image quality throughout the zoom range. The lens is also said to overcome low peripheral brightness that is common in lenses with similar specifications.
The OS function is not incorporated in the Sony versions.
A wide zoom ring ensures convenient handling. Putting the zoom ring in front allows the lens barrel to be more compact. The inner focusing system eliminates front lens rotation, enhancing the stability and allowing the use of circular polarizing filters.
Advanced optical design and Sigma’s Super Multi-Layer Coating reduces flare and ghosting and provides sharp, high-contrast images, even in backlit conditions.
With a minimum focusing distance of 45 cm and a maximum magnification ratio of 1:4.6, this lens is excellent for close-up photography.
The Hyper Sonic Motor ensures quiet, high-speed autofocusing, as well as full-time manual focus override by rotation of the focus ring. With the enhanced AF algorithm, smoother autofocusing is achieved. Full-time manual focus is also possible.
The lens sports a 9-blade rounded diaphragm.
Sigma says the new ergonomic design offers comfortable grips and unobtrusive yet easy-to-use controls. For improved handling, the design of the lens hood, lens cap, and AF/MF changeover switch have been updated.
The lens has a brass bayonet mount.
An optional USB dock, working with the company’s Optimization Pro software, allows photographers to update lens firmware and adjust parameters such as focus.
This lens is eligible for Sigma’s Mount Conversion Service, a paid service that lets you change the mount to use the lens on a different camera body.
The Sigma 24-105 mm f/4 DG OS HSM lens has a suggested retail price of $999.95 and will be available for Canon and Sigma in December, with Nikon and Sony versions available in 2014.