<https://www.canonrumors.com/forum/threads/sigma-will-announce-a-100-400mm-f5-6-3-dg-dn-os-shortly.38665/>
<http://schema.org/headline>
"SIGMA will announce a 100-400mm F5-6.3 DG DN OS shortly"
<https://www.canonrumors.com/forum/threads/sigma-will-announce-a-100-400mm-f5-6-3-dg-dn-os-shortly.38665/#post-836354>