Tech Tuesday Preview: Sigma's f/1.8 Constant Aperture Zoom

April 30, 2013

By RF Staff

Constant aperture zoom lenses aren't anything new and, until now, the record holder was Olympus with two f/2.0 Four Thirds lenses (14-35mm and 35-100mm) launched more than eight years ago.

But now the honor goes to Sigma, with its f/1.8, 18-35mm DC HSM Art lens. Sure, f/1.8 is only about 1/3 of a stop faster than f/2.0 but given that most current constant aperture zooms max out at f/2.8, you'll gain about 1 1/3 stops with the new Sigma model—not an insignificant gain, especially when shooting in dark churches, romantically-lit wedding receptions and other low light scenarios.

Lens size is constant, too, thanks to internal focusing and the lens measures a nicely compact 3.1" x 4.8". It weighs 28.6 ounces and is compatible with Sigma's new USB dock for updating firmware and tweaking parameters such as focus.

The USB dock is expected to be available in May for a price of about $59. Lens price and ship date are still unknown so keep an eye on Sigma's website for updates.