Here we have Tamron's first 70-300mm lens that's designed for use on full-frame mirrorless Sony cameras. The 70-300mm f4.5-6.3 Di III RXD Lens has been developed to make telephoto shooting as easy and as fun as possible. Thanks to its advanced optical makeup, it's ideal for all levels of shooting whether your beginner or a professional photographer. The lens design is made up of 15 elements in 10 groups including an LD (Low Dispersion) lens element and Tamron's BBAR (Broad-Band Anti-Reflection) Coating. To protect this high-quality interior, Tamron has implemented a moisture-resistant construction with seals located at various locations throughout the lens barrel. This is a highly versatile and practical lens. It makes telephoto shooting easier, more enjoyable and what's more, the lens will also take advantage of in-camera features such as Sony's Fast Hybrid AF and Eye AF.