Sigma introduces fastest "Full Frame" zoom lens: 24-35mm f/2
 

24-35mm F2 DG HSM Art f/2

The lens will be available in Sigma, Canon and Nikon mounts

Supposedly shipping in July, price TBD

Sigma Corporation Announces World?s First F2 Zoom Lens for Full Frame Cameras | Sigma Corporation of America

Not as much zoom, or as fast as the 18-35 f/1.8, but still faster than anything else that has existed. I see some use for 5D owners, but if you have something like a C100 or FS100, then this doesn't offer anything over the 18-35mm.