Sigma 18-35 Zoom

To develop a large aperture zoom lens with a maximum aperture of F1.8, it was necessary to solve a variety of technical challenges. 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 minimize astigmatism across the zoom range, Sigma leveraged its extensive experience in reducing optical aberrations and designing advanced structural elements.

Ongoing technological innovation at Sigma's Aizu Factory has also contributed to further enhancements in lens production. 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. 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.