For those looking to get into the super-telephoto game, Tamron has just announced the development of the 100-400mm f/4.5-6.3 Di VC USD Lens for full-frame Canon EF- and Nikon F-mount DSLRs. Packing a variety of specialized elements, including three Low Dispersion (LD), along with an eBAND Coating, this lens aims to provide aberration- and flare-free imagery throughout the impressive range. Also, Tamron has managed to keep it relatively lightweight, at less than 2.5 lb, for easier transport and less strain during shooting.
For fast-moving subjects, the 100-400mm uses a high-speed Dual Micro-Processing Unit and Ultrasonic Silent Drive autofocus system that ensures fast, responsive focusing and effective Vibration Compensation. Also, the lens can focus as close as 4.9' to achieve a maximum magnification ratio of 1:3.6 that is useful for close-up shooting. Employing magnesium in key areas of its construction, this optic is moisture resistant, as well, for use in less than ideal weather, and the front element has a fluorine coating that makes it easier to clean. Additionally, the lens is compatible with Tamron’s 1.4x Teleconverter and TAP-in Console. An optional Arca-type compatible tripod mount is available.