Canon have a f/2 zoom a useful but short range. The 24-70mm and 70-200mm f/2.8 constant aperture zooms are the standard lens for most professional photographers.
Now Tamron announce this, a constant aperture zoom from 35mm to 100mm, this is an extremely useful range with most of the competition being either 24-105 f/4 or 25-120mm f/4.
This lens is going get a lot of attention.
Announced today for the Sony E mount and the Nikon Z mount.