The DG DN series of lenses achieves a supreme combination of optical performance and compactness that could not have been possible with lenses for single-lens reflex cameras because its optics is specifically designed for camera with a short flange back distance.
Thanks to the stepping motor system that is optimized for both phase detection AF and contrast AF, the SIGMA 100-400mm F5-6.3 DG DN OS | Contemporary L-Mount makes shooting with the video or eye-tracking AF very smooth.