Tamron just revealed its newest ultra-telephoto zoom. Meet the Tamron 100-400mm F4.5-6.3 Di VC USD (Model A035) for full-frame Canon and Nikon DSLRs—a lens that combines compact, lightweight construction with 'superior' image quality and 'fast and precise AF', according to Tamron. The lens' tagline: heavyweight performance in a lightweight lens.
The new lens was revealed this morning, and its claim to fame is its size and weight. At just 39.3 oz., the new 100-400mm lens is the lightest in its class thanks to the use of magnesium allow in 'key areas' of the lens barrel. Inside that barrel you'll find 17 lens elements in 11 groups—including three low dispersion (LD) elements—and Tamron's high-speed Dual MPU that allows for 'fast and precise AF' as well as four stops of stabilization.