The bright f/1.8 maximum aperture on the Sigma 135mm F/1.8 DG HSM Art is well-suited for working in low-light conditions and also provides greater control over the focus position when using shallow depth of field techniques.
Two F Low Dispersion (FLD) and two Special Low Dispersion (SLD) elements are featured in the optical design, and help to reduce color fringing and chromatic aberrations for improved clarity and color accuracy.
A Super Multi-Layer Coating has been applied to lens elements in order to minimize lens flare and ghosting and contribute to producing contrast-rich and color-neutral imagery, even in backlit conditions.
Nine-blade rounded diaphragm contributes to a smooth and pleasing bokeh quality.
The integrated HSM (Hyper Sonic Motor) on the Sigma 135mm F/1.8 DG HSM Art realises quick and quiet autofocusing, which is further complemented by an optimized AF algorithm to produce smoother focusing performance.
The HSM also permits full-time manual focus control simply by rotating the focus ring at any time.
The lens is constructed using a Thermally Stable Composite (TSC) material, along with traditional metals, for greater precision and use in wide temperature variations.
The bayonet mount on the Sigma 135mm F/1.8 DG HSM Art is constructed from brass for ensured accuracy and durability. Additionally, rubber sealing is incorporated in the mount design to render it dust- and splash-resistant.
This Sigma 135mm F/1.8 DG HSM Art lens is compatible with the optional Sigma USB Dock for fine-tuning different lens characteristics and updating its firmware.
For more info see www.sigmalens.com