Via Tamron’s site:
Go to extremes with the world’s first* 22.2x ultra-telephoto all-in-one zoom.
Introducing the world’s first ultra-telephoto all-in-one zoom lens for the APS-C format. With a focal length range of 18-400mm and 22.2x zoom, it has an ultra-telephoto range equivalent to 620mm in the 35mm format. This brings distant subjects closer, while providing perspective-flattening effects that are only possible with an extreme telephoto lens. Plus it offers exceptional optical performance across the entire zoom range—from wide angle to ultra-telephoto. With this new lens—and its Moisture-Resistant Construction—Tamron brings the art of photography to the joy of travel. Now you can use the same lens to shoot everything from stunning landscapes and neon-lit cities to detailed portraits and delicate flora. The ultra-telephoto range makes it just as easy to photograph animals and sports. And with a maximum magnification ratio of 1:2.9, you can even enjoy tele-macro photography.