Presenting impressive reach in a relatively compact design, the Leica L-mount 100-400mm f/5-6.3 DG DN OS Contemporary lens, from Sigma, is a versatile telephoto zoom mixing a hand-holdable design with apt optical performance. A series of low dispersion glass elements are used to achieve high clarity and color accuracy throughout the zoom range, and to suppress chromatic aberrations and color fringing. Complementing the optics is intuitive handling, in which a stepping motor delivers fast, near-silent autofocus performance along with fine-tuned manual focus control. Additionally, four stop-effective optical image stabilization helps to reduce the appearance of camera shake for sharper handheld shooting and this 100-400mm is also compatible with the optional TS-111 Tripod Socket for steady shooting atop a tripod or monopod. As part of the Contemporary line within Sigma's Global Vision series, this lens is designed to achieve a balance between convenience and performance, and meshes a compact, lightweight build and versatile handling with notable optical attributes. Telephoto zoom is designed for full-frame L-mount mirrorless cameras, but can also work with APS-C models where it provides a 150-600mm equivalent focal length range. One F Low Dispersion (FLD) element and four Special Low Dispersion (SLD) elements markedly reduce chromatic aberrations and color fringing throughout the zoom range for improved clarity and color accuracy. Optical image stabilization compensates for up to four stops of camera shake to help realize sharp imagery when shooting handheld with slower shutter speeds. Integrated stepping motor realizes quick and quiet autofocus, which is further complemented by an optimized AF algorithm to produce smoother focusing performance. At the 100mm end of the zoom range, a minimum focusing distance of 3.7' is available, and at the 400mm end, the minimum focusing distance is 5.2' with a maximum magnification of 1:4.1. Integrated AFL button can be programmed to adjust various shooting settings and the lens also features a focus limiter switch for faster focusing performance within certain distance ranges. There is a zoom lock switch to prevent the barrel from accidentally extended. Rounded 9-blade diaphragm contributes to a pleasing bokeh quality. 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. Compatible with optional TS-111 Tripod Socket for working atop a tripod or monopod; the included PT-31 Protective Cover can be attached to the lens to maintain a seamless appearance if the tripod socket is not used. Compatible with optional Sigma TC-1411 1.4x and TC-2011 2x teleconverters. This lens is compatible with the optional Sigma UD-11 USB Dock for fine-tuning different lens characteristics and updating its firmware.