Sigma 17-40mm f/1.8 DC Art Lens, Autofocus, Filter 67mm (L-Mount) - 6030113 Sigma introduces a new zoom lens for APS-C mirrorless cameras with an f/1.8 aperture throughout the entire zoom range, the 17-40mm f/1.8 DC Art Lens. Featuring prime-like optical performance and video-friendly design and functionality, its wide-to-normal focal range means a lighter kit bag without surrendering image quality. Design and Performance The lens features a total of 17 elements in 11 groups, with four aspherical and four Special Low Dispersion elements to minimize flare and ghosting and suppress various aberrations. This results in an optical performance that meets or exceeds that of other Sigma Art lenses, including the 18-35mm f/1.8 DC HSM Art lens. Along with its 11-blade, rounded diaphragm, the design promotes sharpness and a large, smooth bokeh when used wide open. In addition to the f/1.8 maximum aperture, the lens also maintains an 11" minimum focusing distance across the entire zoom range. It achieves a maximum magnification ratio of 1:4.8 at its longest focal length, increasing depth of field and versatility in tight spaces. Video Production Designed with video creation in mind, the lens' bright f/1.8 aperture and wide-to-normal zoom range make it a versatile tool ideal for single-shooter, run-and-gun setups. An internal zoom design maintains the overall length during use, making it easy to balance on gimbals. The design also suppresses focus breathing for smooth movement across the focal range. Sigma's high-speed, high-response linear actuator autofocus remains both quiet and accurate, while manual focusing is improved with click-and-lock mechanisms.