Continuing on delivering a set of unique lens for Sony E-mount, Tamrom just launched a new bright constant-aperture zoom for Sony Full-Frame mirrorless digital cameras. The Tamron Di III 70-180mm F/2.8 VXD is designed specifically for to deliver the lightest possible constant-aperture telephoto zoom lens and even manages to provide a weatherproof constructions.
The Tamron Di III 70-180mm F/2.8 VXD is medium telephoto lens which keeps a bright maximum F/2.8 aperture throughout its zoom range. The external zoom is quite packed with optical elements which makes the lens a little front-heavy and so Tamron included a locking mechanism to prevent zoom creep. As a match for Sony mirrorless which now all sport 5-axis image-stabilization systems, this new Tamron lens does not include stabilization to save weight and complexity, allowing it to sell at a lower cost. The only downside is that uses of low-end Sony APS-C mirrorless will not get stabilization at all with this lens.
A newly designed VXD motor promises faster autofocus while reducing the AF-range which is a highly unusual choice. The electronic autofocus motor can focus down to 85cm at any focal-length which gives it a magnification of 0.21X when set to 180mm. Switching over to Manual Focus though, the lens can focus down to 27cm which gives a much better 0.5X magnification. In theory, using a limited focus-range would allow the lens to autofocus more quickly.
What is really interesting about the new Tamron Di III 70-180mm F/2.8 VXD is that it offers a unique compromise. While there are already two longer 70-200mm constant aperture zoom made by Sony for their Full-Frame mirrorless, cutting down just 20mm on the long-end allowed Tamron to make their F/2.8 lens lighter than the Sony F/4 version while providing the same F/2.8 aperture a lens that weighs a full pound more!
Tamron expects to ship this new lens mid-May for a suggested retail price of $1200 USD. Those interested can already place pre-orders at B&H Photo or Adorama. No charge will be made until the lens actually ships, while ensuring to be among those to receive it first.