SIGMA 18-35mm F1.8 DC HSM - What makes a standard lens ideal for you? Certain important qualities are required, such as fast maximum aperture, versatility for snap shots, portraiture and indoor photography plus a good combination of a wide range of focal lengths in a compact design. SIGMA 18-35mm F1.8 DC HSM is the first zoom lens ever to achieve a maximum aperture of f1.8 throughout the zoom range. It is a wide aperture, standard zoom-lens for digital single lens reflex cameras with APS-C size sensors. *1 The lens has a focal range equivalent to 27mm - 52.5mm in a 35mm format and it can cover the angles of view of multiple fixed focal length lenses. This wide aperture, standard zoom lens enables the photographer to expand creative possibilities on any occasion. *1 - As of April, 2013 Sigma's Art line delivers high-level artistic quality. Sigma is organizing all its interchangeable lenses into three product lines; Contemporary, Art and Sports. Designed with a focus on sophisticated optical performance and abundant expressive power, the Art line delivers high-level artistic expression. Developed with the maximum emphasis on artistic touch, they are designed to meet the expectations of users who value a creative, dramatic outcome above compactness and multifunction. Along with landscapes, portraits, still-life, close-up and casual snaps, they are perfect for the kind of photography that unleashes the inner artist. Ideal for studio photography, they offer just as much expressive scope when capturing architecture, starry skies, underwater shots and many other scenes. Excellent Usability. A zoom lens is very convenient as it offers various angles of view just by rotating the zoom ring. However, the down side was that no zoom lens ever offered a faster aperture than f2.8 which led photographers to select fixed focal length lenses for brighter images. While the aperture value of prime lenses is superior to zoom lenses, their field of view is always the same, and therefore it was always necessary to carry many fixed focal length lenses. SIGMA 18-35mm F1.8 DC HSM is a next generation lens that can deliver images at f1.8 aperture throughout its focal length. The bright viewfinder is very helpful for checking the focus and composition of the image. If it is compared with a lens of F2.8, the faster shutter speed and the shallow depth of field of F1.8 further expands creativity. From wide to standard range this lens offers the excellent versatility and performance of multiplefixed focal length lenses. Fruit of cutting edge technology. To achieve a wide zoom lens with a maximum aperture of f1.8, various technical problems need to be overcome. As the aperture value gets larger, the depth of focus becomes shallower, thus it makes the lens design extremely complicated in order to compensate for various distortions, such as spherical, axial chromatic and astigmatic aberration along with curvature of field. In order to compensate for astigmatic aberration across the entire focal range, Sigma has relied on the experience and know how gained when designing their super wide angle zoom lenses such as SIGMA12-24mm F4.5-5.6 II DG HSM and SIGMA 8-16mm F4.5-5.6 DC HSM. In addition, the technological innovation at our Aizu factory also contributes to better lens production. It has enabledSigma to develop a wide glass-molded ...