The fastest zoom lens in the land
For quite some time, F/2.8 has been the pinnacle when it comes to zoom lens aperture, but Sigma has raised the stakes a bit, at least for APS-C sensor DSLRs. Their new 18-35mm DC HSM zoom lens maintains a maximum aperture of F/1.8. That's a pretty big deal.
The new lens has a full-frame equivalent field of view of 27-52.5mm, making it a little shorter than the typical 24-70mm standard zoom. it focuses to a minimum distance of 11-inches and has a maximum magnification ratio of 1:4.3, which isn't exceptionally close for a lens like this.
The main draw, though, is clearly the fast aperture. They manage it using their glass-molded aspherical elements and Super-Low Dispersion glass. They also claim to have mitigated the distortion, even at the widest focal lengths.
The lens ships with a petal hood and is compatible with Sigma's USB dock for micro adjustments. There's a lot of glass inside the lens, using 17 elements in 12 groups. And while the maximum aperture is extremely wide, the smallest aperture is just F/16, which is a little odd for a wide angle lens that could be appealing to landscape photographers.
One thing we're glad to see is the 9-blade circular diaphragm, because with an F/1.8 aperture, bokeh will be plentiful.
There's no official pricing or availability information just yet, but we'll be keeping a very close eye on this lens. Between their excellent fast full-frame primes and now this, Sigma has been doing some really cool things with their glass.