Its bright viewfinder makes it easy to confirm focus and compose perfect shots. The 18-35mm F1.8 DC HSM next-generation large-aperture standard zoom lens is the world’s first* to deliver F1.8 brightness throughout the zoom range. Although fixed focal lenses have been superior to zoom lenses in terms of f-number brightness and overall performance, they offer only a fixed angle of view, requiring photographers to carry several with them and change lenses as necessary. The downside, however, is that F2.8 has been the limit of zoom lens brightness, forcing photographers to select fixed focal length lenses for brighter f-numbers. Zoom lenses are extremely convenient, providing a wide range of angles of view with just a twist of the zoom ring. Thanks to its hard-earned knowledge of lens design and advanced lens manufacturing techniques, SIGMA has succeeded in creating a lens that offers F1.8 throughout the zoom range, as well as exceptional image quality at wide open aperture. Advanced production technologies have made possible a large-diameter molded glass aspheric lens, which teams up with SLD (Special Low Dispersion) glass elements to optimize power distribution and minimize axial chromatic and spherical aberration and field curvature. Ongoing technological innovation at SIGMA’s Aizu Factory has also contributed to further enhancements in lens production. SIGMA gained this know-how when it developed such super wide angle zoom lenses as the SIGMA12-24mm F4.5-5.6 II DG HSM and SIGMA 8-16mm F4.5-5.6 DC HSM. ![]() ![]() To minimize astigmatism across the zoom range, SIGMA leveraged its extensive experience in reducing optical aberrations and designing advanced structural elements. ![]() As the f-number decreases, so does the depth of focus, making it extremely difficult to minimize spherical aberration, axial chromatic aberration, astigmatism and field curvature. To develop a large aperture zoom lens with a maximum aperture of F1.8, it was necessary to solve a variety of technical challenges.
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