New firmware

• It becomes fully functional with the Canon Digital Cinema Camera EOS C300 Mark II.
• For SIGMA 20mm F1.4 DG HSM | Art Canon, this lens firmware update also corrects the phenomenon that the images show some underexposure when “Evaluative Metering” or “Center-weighted Average Metering” is selected on Canon EOS-1D X Mark II.

http://www.sigma-global.com/download/

https://www.ephotozine.com/article/sigma-24-35mm-f-2-dg-hsm---a-lens-review-27974

Lens is very good wide open across the full frame sensor. Center performance stays at a very high level over the zoom-range. The APS-C/DX-corner is quite contrasty as well but is a bit softer than the center. There is also some gradual deterioration when you zoom towards the long end. The FF/FX-corner is a bit hazy but offers plenty resolution none-the-less up to 31mm but drops a notch in quality at 35mm.

http://www.cameralabs.com/reviews/Sigma_24-35mm_f2_DG_HSM_Art/

Now in stock in more places

• US - http://www.bhphotovideo.com/c/product/1162797-REG/sigma_24_35mm_f_2_dg_hsm.html
• UK - http://www.amazon.co.uk/gp/product/B011QXQ41S/
• DE - http://www.amazon.de/gp/product/B011QXQ41S/
• FR- http://www.amazon.fr/gp/product/B011QXQ41S/

http://dc.watch.impress.co.jp/docs/review/lens_review_2/20150821_716931.html

http://www.lensrentals.com/blog/2015/07/a-quick-look-at-the-new-sigma-24-35-f2-art

Another review

http://petapixel.com/2015/07/21/review-sigmas-24-35mm-f2-art-is-like-a-prime-lens-that-zooms/

Samples

http://www.popphoto.com/sample-image-gallery-sigma-24-35mm-f-2-dg-hsm-art-full-frame-zoom-lens

I believe the idea is to compete with primes, by offering something that gets close to the speed and quality of a prime while maintaining the convenience of a little zoom range...makes sense to me anyway...

Sigma Corporation of America, a leading DSLR lens and camera manufacturer, today announced that the new Sigma 24-35mm F2 DG HSM Art lens will become available in late July for the street price of $999.

The 24-35mm F2 DG HSM Art lens is the market’s first full-frame zoom that allows photographers to carry one fast aperture lens that can do the work of three popular fixed focal length lenses – the 24mm, 28mm and 35mm. It includes an optimized autofocus (AF) algorithm for smooth, fast, and accurate focusing, a manual focus (MF) override functionality, and is made of Thermally Stable Composite (TSC) reducing its size and weight.

Built upon the impressive versatility offered by Sigma’s 18-35mm F1.8 DC HSM Art lens, the new 24-35mm continues the Art line tradition of top optical performance that’s comparable to Sigma’s 24mm F1.4 DG HSM Art and 35mm F1.4 DG HSM Art. It offers optimized lens power distribution, and minimizes spherical aberration, axial chromatic aberration and field curvature. The Sigma 24-35mm F2 DG HSM Art lens also features a video-friendly, inner focusing system that eliminates front-lens rotation, enhancing the lens’ stability as well as a Hyper Sonic Motor (HSM) that ensures a silent, high-speed AF function.

Nikon preorder - http://www.adorama.com/SG2435NK.html