Collected here are links to image samples from, and reviews and user opinions on the Sigma 180mm f/3.5 EX APO IF DG HSM lens for the Canon EOS mount.
A hummingbird with the Canon EOS 1D Mark II N
Ian Grey shares this super shot of a female Ruby Throat hummingbird (uncropped, resized photo). He also notes the lack of shutter delay (as compared to his EOS 20D camera) on the 1D Mk2 N. Shutter speed and aperture were approximately 1/250 sec and f/8 each.
Miscellaneous resources
Visit the official site for the Sigma 180mm lens for specifications and manufacturer description. Interesting bit of trivia: The snake photo you see at the Sigma site was shot by Ian Grey, the same gentleman who posted the hummingbird photo that I linked to at the beginning of this post.
To make sense of the lens nomenclature, go to Sigma Imaging, UK.