Tamron’s latest is a highly capable zoom for Sony APS-C shooters

Newly announced and freshly available for pre-order: the Tamron 17–70mm f/2.8 Di III-A VC RXD is scheduled for availability on January 14th, 2021, at a price of $799.99.

The bright, fast f/2.8 aperture is a familiar sight on Tamron’s excellent line of lenses for full-frame E-mount, as is the 67mm filter thread size, but “Di III-A” is a new designation for Tamron. Can you crack the code? That’s right: the “A” is for APS-C!

A quick refresher on Tamron terminology: “Di” stands for “Digitally integrated” and indicates lenses designed to function well with digital cameras. There are four Di designations, as follows…

Di: DSLR lenses whose imaging circle will cover a full-frame sensor (or 35mm film)
Di II: DSLR lenses whose imaging circle will cover an APS-C sensor
Di III: Lenses designed for mirrorless interchangeable-lens cameras whose imaging circle will cover a full-frame sensor
Di III-A: Lenses designed for mirrorless ILCs whose imaging circle will cover an APS-C sensor

A common misconception is that APS-C lenses are not “as good” as full-frame lenses, but that is certainly not a given. On the contrary, for the massive population of imaging enthusiasts who are perfectly happy using a camera with an APS-C-sized sensor—myself included!—a lens that is designed to fit the sensor you’re actually using can provide quality that equals any full-frame lens in a significantly smaller and lighter package—if the lens is manufactured with the same level of care. And for this one? That seems to be the case.

Considering the runaway popularity of Sony’s α6000-series cameras, it’s a bit surprising we haven’t seen more attention given to top-quality APS-C lenses, especially considering that one of the biggest reasons people choose one of these cameras is to carry a more compact kit without sacrificing quality. In any case, the 17–70mm (25.5–105mm full-frame equivalent field of view) promises pro performance with a portability only possible in a purpose-built piece.

16 elements in 12 groups, including two GM (“glass-molded aspherical”) and one hybrid aspherical, have been meticulously engineered to provide edge-to-edge sharpness and coated to minimize distortion and aberrations. Add AI-informed vibration control to the quality of the glass and you’re looking at a recipe for crisp, clean images, all day long. The front element is fluorine coated to make cleaning a snap, of course, and the whole body is moisture resistant thanks to tight construction and moderate sealing.

The AF system utilizes Tamron’s Rapid eXtra-silent stepping Drive, pictured above right, so you won’t have to worry about grinding noise in your videos. It’s also fully compatible with camera-specific features like Sony’s Eye AF and Fast Hybrid AF!

A minimum focusing distance of only 7.5″ at 17mm rounds out the utility of this lovely lens, and it’s all packed into a supremely-baggable 4.7″, 18.5 oz frame.

Check out some sample images below (click to enlarge), then click here or head over to a Mike’s Camera near you to get your name on the pre-order list. Supply is still significantly impacted by the ongoing pandemic, so if you’re interested you’ll definitely want to get in line as soon as possible.

Need something that can be unwrapped while you’re waiting for January 14th? Check out our holiday gift guide for more great gear.

Sample images

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