Today, Tamron has announced its latest full-frame E-mount lens, the 70-300mm f/4.5-6.3 Di III RXD. Not only is it quite thrifty at $549, it’s also the smallest and lightest telephoto zoom lens available for the Sony mount.
Measuring in at 5.80 inches in length with a 3.03 maximum diameter, the new 70-300mm weighs just 1.2 pounds. Like the other Tamron full-frame mirrorless lenses, it has a 67mm filter thread for compatibility across the range. Used on a crop sensor camera body like the Sony a6600, the 70-300mm turns into an effective 105-450mm lens.
Inside, the lens houses 15 elements in 10 groups, including one low dispersion element and Broad-Band Anti-Reflection coating for optimized image quality. The lens features a moisture-resistant construction and has a seven-bladed circular aperture.
Tamron promises great performance with Sony’s various autofocus features such as Real-time Tracking, Eye AF, and DMF through the utilization of its RXD stepping motor. According to Tamron, the 70-300mm “can be used discreetly in concert halls and other situations that require low noise levels, and for video recording.” It has a close focusing distance of 31.5 inches at the wide end and 59.1 inches at the telephoto end.
The Tamron 70-300mm f/4.5-6.3 Di III RXD will begin shipping on October 29, 2020.
Having used Sony IBIS enough I wouldn't want a lens this long without OS. It's certainly priced well but I call these carrot lenses. They are missing too many features to keep but cheap enough to get people to bite. I'm sure there are a few people that it will for. Optically it's probably good. Although it's a tough decision considering the next step up is twice the price and yet again when you want something even better than that. Right now the best deal you can get is the Sigma 100-400.