The Tamron 100-400mm F/4.5-6.3 Di VC USD (Model A035) is a highly portable, ultra-telephoto zoom lens with AF precision for shooting in-the-moment action clearly and easily. 3 LD (Low Dispersion) glass elements are used and effectively positioned to take away aberrations that are known to occur with a telephoto lens. And Tamron’s proprietary eBAND (Extended Bandwidth & Angular-Dependency) Coating prevents reflections, giving you clearer, more vivid images. With a lens barrel made primarily of magnesium at selected area, the Model A035 is the lightest zoom in the ultra-telephoto category*, making it ideal for handheld shooting over long periods of time. Plus, Moisture-Resistant construction and a Fluorine-Coating on the front element provide additional protection when shooting outdoors.