Sigma made waves this morning, announcing the world’s first zoom lens with a fixed f/1.8 aperture. The 18-35mm F1.8 DC HSM Art zoom lens features a modest 2x zoom ratio, but is faster than some prime lenses. Its light-gathering capability is four times of that as a standard 18-55mm f/3.5-5.6 lens at the wide end and about six times at the 35mm setting, where kit zooms typically close down to f/4.5.

Previously even the best zoom lenses topped out at f/2.8 when covering the APS-C image sensor found in mainstream D-SLRS; those lenses capture a little less than half the light as this 18-35mm. Olympus had previously claimed the fastest zooms. It offers a pair of f/2 optics that are compatible with its Four Thirds SLR system; but the image sensors in those cameras aren’t quite as big as an APS-C camera.

The 18-35mm range is equal to a 27-52.5mm range on a full-frame camera. This covers a wide-angle to standard-angle field of view. It can focus on objects as close as 11 inches, which will allow you to create some serious background blur when shooting at f/1.8. It’s part of Sigma’s Art lens series, optics that are designed to let photographers capture artistic images. The aperture features a 9-blade design with rounded edges, so expect bokeh to be smooth.

It’s a big lens, measuring 4.8 by 3.1 inches (HD), weighing in at 1.8 pounds, and requiring 72mm filters. The front element doesn’t rotate, so using a polarizing filter is possible.  A petal-type lens hood is included to reduce flares and increase contrast when shooting. It is compatible with the Sigma USB Dock, an innovative accessory that allows you to update firmware and adjust focus settings by attaching the lens to a computer.

No word on what mounts the lens will be compatible with, but expect Canon, Nikon, and Sigma SLRs to be supported. Pricing and availability have not yet been set.