"Sigma 135mm F1.8 DG HSM Art Boasting outstanding sharpness and great IQ from edge to edge, the 135mm F1.8 Art lens enters the market as Sigma's new premiere mid-range telephoto prime lens. Ideal for events such as concerts, indoor sports, conferences and press events, the 1.8 F-stop delivers greater ""shallow depth of field"" and isolation of subjects. The outstanding compression effect makes it equally as powerful for up-close and full-length portraits. Its new large hyper sonic motor (HSM) provides ample torque to the focus group for optimal speed while the acceleration sensor detects the position of the lens for compensation focus groups for factors including gravity, producing faster and more responsive AF. Equipped with a focus limiter, the 135mm F1.8 Art can be easily optimized for a variety of distances and situations|Full Frame Lens with APS-C compatibility|Stunning compression effect for portrait photography|Ideal Use: Studio photography, portrait photography and event photography|4 Year USA Warranty"