Tamron has announced development is underway for its new 100-400mm F/4.5-6.3 Di VC USD (Model A035) lens. Compact and lightweight at 39.3 ounces, the ultra-telephoto zoom is designed for full-frame Canon and Nikon DSLRs. Tamron says important areas of the lens barrel are constructed of a magnesium material that’s meant to “improve weight reduction, strength and portability” in the lens. Release is scheduled for some time by the end of 2017.

The new lens features optical construction consisting of three LD (Low Dispersion) lens elements to mitigate chromatic aberrations, plus Tamron’s anti-reflection eBAND (Extended Bandwidth & Angular-Dependency) Coating to help eliminate ghosting and flare.

The newest Tamron lens models feature a high-speed Dual MPU (Micro-Processing Unit) control system, and so will the new 100-400mm. The system is designed to provide the lens with “quick and highly responsive autofocus performance and outstanding vibration compensation.”

Other features include a 59-inch minimum object distance, a 1:3.6 max magnification ratio and a fluorine coating to protect the moisture-resistant lens from the elements. The 100-400mm is compatible with Tamron’s 1.4x teleconverter and the TAP-in Console for lens adjustments.