1.SIGMA's 5th DG DN lens with an exclusive new design for full-frame mirrorless cameras 2. Uncompromising image quality The lens construction of the SIGMA 100-400mm F5-6.3 DG DN OS | Contemporary comprises 16 groups and 22 elements, with one FLD and four SLDs used for the effective correction of aberrations and distortions. Built on the latest optical design technology and optimized for mirrorless systems, the new lens ensures the same high-resolution image quality all the way to the edges. In addition, it constantly achieves high levels of optical performance and makes the most of its capabilities as a zoom lens in any condition, at every focal length from wide to telephoto, and from close-up shots to telephoto photography.