New Sigma SLR lens: 24-105mm f4 OS DG HSM Art series (C/N/A/P/S) [official now]
UPDATE 10/16/13 at 1:36am ET: the lens is now officially announced! The links below work again! No price as far as I can tell. Sigma makes announcements in parts, so the price will probably be revealed later as we get closer to release.
The f4 zoom party continues with Sigma, showing the new 24-105mm f4 DG OS HSM SLR lens on their website. The lens is part of their new "Art" series. One of the benefits of this new "Art/Sports/Etc" grouping is you can easily tell new lenses from older lenses.
The lens will come out in Canon first, followed by Nikon, Sony Alpha, Pentax K, and Sigma SLR.
Each of the boxes under "Product Features" at the Sigma website is a separate page of its own revealing more details about the lens. These include vignetting and distortion charts and MTF charts along with the detailed specs and diagram, and charts in one page.
Price and availability, in typical Sigma fashion, will come later.