A high ratio zoom lens often requires compactness and enhancement of additional features, to be capable enough to cover various shooting scenes with convenience and versatility. Even with a high ratio zoom lens, our goal is to satisfy enthusiastic photographers with the versatility of the lens and its optical performance. Therefore, we sought for the point where all the pieces, such as specification, performance and size, fall into place, and this lens is the fruit of this journey. Enjoy the performance of a high ratio standard zoom lens that has "the highest standard for excellent image quality based on each concept", of which product lines SIGMA has renewed and established with SIGMA Global Vision.
The degree to which light is refracted by glass depends on the light's wavelength. This fact causes different colors of light to focus at slightly different points. The result is chromatic aberration, the color fringing that is particularly noticeable in telephoto lenses. Most chromatic aberration can be removed by combining a high-refractivity convex lens element with a low-refractivity concave element. Yet residual chromatic aberration known as “secondary spectrum” may still remain.To minimize this secondary spectrum, which can be a serious issue with conventional lenses, SIGMA lenses feature up to three types of exclusive low-dispersion glass offering superior performance: ELD (Extraordinary Low Dispersion), SLD (Special Low Dispersion) and FLD (“F” Low Dispersion). In particular, FLD glass offers ultra-low dispersion in combination with high transmittance and the anomalous dispersion characteristics of fluorite. Meticulous deployment of these types of exclusive low-dispersion glass and optimization of power distribution gives SIGMA lenses superlative image rendition undiminished by residual chromatic aberration.
SIGMA lens technology