The Leica L-mount 90mm f/2.8 DG DN Contemporary Lens from Sigma is a short-telephoto prime with impressive optical performance. It is well-suited for portraiture and selective everyday shooting and offers a fast f/2.8 aperture for controlling the depth of field and working in less-than-ideal light. This lens includes an aspherical element and five special low-dispersion elements to control a variety of aberrations and achieve notable sharpness and clarity. A rounded nine-blade diaphragm lets you achieve a pleasingly smooth bokeh, and the lens's all-metal body is 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. One aspherical element helps to control distortion and spherical aberrations for a high degree of sharpness and accurate rendering. The rounded nine-blade diaphragm contributes to a smooth and pleasing bokeh quality.