The Sony E-mount Sigma 65mm f/2 DG DN Contemporary Lens is a shot-tele/long-normal prime offering a unique field of view well-suited to portraiture and selective everyday shooting. Complementing the slightly longer focal length is a bright f/2 design that helps to maintain a portable form factor while also contributing to low-light performance and depth of field control. Optically, this 65mm f/2 includes a pair of aspherical elements and one low dispersion element in its design to control a variety of aberrations and achieve notable sharpness and clarity.  As an I Series lens, too, this lens incorporates a manual aperture ring and all-metal barrel constriction into its design for enhanced tactility. Additionally, there is a rounded nine-blade diaphragm for smooth bokeh quality and the lens housing is also weather-sealed to suit working in inclement conditions. I Series lens emphasizes a sleek and stylish physical design that is built to the same operational standards of Sigma's Cine lenses, including a mechanical aperture ring, knurled metal components, and various switches and tactile controls for intuitive operation. Bright f/2 maximum aperture strikes an ideal balance between speed and size and manages to maintain a compact physical profile while also offering low-light performance and depth of field control. Two aspherical elements help to control distortion and spherical aberrations for a high degree of sharpness and accurate rendering. The integrated stepping motor realizes smooth and quiet autofocus, which is further complemented by an internal focusing design to promote greater responsiveness. Brass bayonet affords improved mounting accuracy and rigidity and rubber sealing is incorporated in the mount's design to render it dust- and splash-resistant.