Probably the most common lens that pro photographers use is a standard zoom with a constant aperture. Up until now, Fujifilm has lacked such a lens for their X series of cameras. That's all changing with the announcement of a 16-55mm f/2.8 lens to add to their already impressive lineup.
As far as standard zooms go, Fujfilm users have had to choose between the lackluster 16-50mm f/3.5-5/6 or the nicer 18-55mm f/2.8-4. The new 16-55mm looks to trounce both of those with a constant f/2.8 aperture for solid low light performance, and a pretty impressive zoom range which equals 24-84mm in full-frame terms. This gives Fujifilm an advantage over their closest competitor in the APS-C mirrorless market, Sony, who's closest offering is a 16-70mm f4. Despite featuring optical stabilization where the Fujifilm doesn't, the Sony's f4 aperture is a significant drawback.
Another killer feature from Fujiilm is the fact that the 16-55mm is also weather-sealed against water and dust. It's actually Fujifilm's first weather-sealed lens, and more are expected to come. That makes it a great pairing with the X-T1, the only weather-sealed Fujifilm body.
The 16-55m f/2.8 lens is priced at $1200 and will be available in February. Expensive, for sure, but along the lines of what you pay for a premium standard zoom from any brand. As long as the new glass can deliver the terrific image quality Fujifilm is known for, expect this lens to find a place in many-a-camera bag.