Sigma's improved optical design situates exclusive low-dispersion convex elements at the front of the lens to achieve both a compact and lightweight lens construction and high optical performance with excellent aberration correction. With 20 lens elements in total arranged in 14 groups, including three FLD elements and two SLD elements, the lens effectively prevents flare and ghosting and promotes image clarity. The lens body is built from Thermally Stable Composite and magnesium for a robust, dust- and splash-resistant construction. The front element also sports a water- and oil-repellent coating to protect the lens from debris.

The HLA (High-response Linear Actuator) focusing motor introduces unprecedented speed, precision, and silence into the Sigma autofocus system. The HLA also offers improved focus following performance for sports photography and other subjects in motion such as cars, planes, or birds in flight, ensuring that the decisive moment is not missed.