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Tamron 17-70mm F/2.8 Di III-A VC RXD Lens Review

Compact and fast zoom for Sony's E-mount APS-C mirrorless cameras packs a punch
Photo of Tamron 17-70mm f/2.8 lens

If you own a Sony E-mount APS-C mirrorless camera and are looking for a high-performing all-around zoom lens to shoot with, you really can’t go wrong with the new Tamron 17-70mm F/2.8 Di III-A VC RXD (Model B070). I tested this relatively compact – 4.7 inches in length; 18.5 ounces in weight – and relatively affordable – $799 – Tamron lens with Sony’s premium E-mount APS-C camera, the A6600, for a few weeks and found it be a killer combo for a variety of shooting situations.

The new 17-70mm is Tamron’s first fast aperture zoom lens for mirrorless cameras with APS-C sensors and features a constant maximum aperture of f/2.8 across the entire 4.1x zoom range, which is equivalent to 25.5-105mm on a full frame camera. While you can use this lens with Sony’s full-frame E-mount cameras, it will capture images in a reduced APS-C crop on the sensor. Consequently, I’d suggest only considering this lens if you have a Sony APS-C camera; using it with a full framer sort of defeats the purpose.

The 17-70mm F/2.8 Di III-A VC RXD, as its model name suggests, is equipped with Tamron’s VC (Vibration Compensation) optical image stabilizer to reduce camera shake when capturing still photos and adds AI (artificial intelligence) technology to help stabilize footage when shooting video. Read on to find out what I thought of this small but powerful zoom lens in my Tamron 17-70mm F/2.8 Di III-A VC RXD review.

Photo of Tamron 17-70mm f/2.8 lens 2


Build & Features

As mentioned, the Tamron 17-70mm F/2.8 Di III-A VC RXD is smaller and lighter than I expected considering the zoom range and fast f/2.8 constant aperture, and when paired with the Sony A6600, you’ll feel considerably less encumbered than shooting with a full-frame rig. Pro photographers should find this a welcome alternative/relief to the heavy duty gear they bring on assignments, and it could easily be a second lens-body they add to their photo bags for shooting behind-the-scenes videos, scouting locations, capturing test shots etc.

At the same time, while I like the portability of this combo, when you extend the lens to 70mm, it adds about an inch to the lens’ length, which front loads the Sony A6600’s stripped down camera body. It’s a bit unbalanced though I appreciated Tamron gave this lens the same high-quality, moisture-resistant build as its full-frame optics. About three inches in diameter, Tamron 17-70mm F/2.8 Di III-A VC RXD felt comfortable in my hand and the large, rubber zoom ring has grippy ridges, making it easy to turn, even with gloves on. Meanwhile, fluorine coating on the front lens element helped prevent smudging.

While the lens’ sleek, modern-looking surface is appealing, I was surprised that there are no switches or buttons on the barrel for changing from autofocus to manual focus or to turn the image stabilization (VC) on or off. You need to make these adjustments via the camera’s menu system, which adds a step. When I asked Tamron about this design choice, the company said it was in the interest of increasing the lens’ portability.

Test photo for Photo of Tamron 17-70mm f/2.8 lens review
I captured this shot while standing on a rock just at the edge of this small waterfall. The Tamron 17-70mm F/2.8’s VC image stabilizer helped out a lot since there was no place to put a tripod.

“The 17-70mm F2.8 is a lens with a large aperture and high zoom magnification designed to be as compact and lightweight as possible,” Tamron said in an emailed statement to me. “Based on this concept, it is not equipped with VC on/off or AF/MF that can be switched on the lens side. In order to realize the concept of this lens, (‘compact size for high mobility’), we have taken into consideration the high expandability of the cameras that allow you to assign various functions to each button on the camera according to your preference.”


Fair enough. Tamron certainly packs a lot of features into this svelte and fast lens. The 17-70mm F/2.8 VC lens has the same small, 67mm filter diameter as Tamron’s non-VC mirrorless lenses, along with its RXD (Rapid eXtra-silent stepping Drive) autofocus (AF) system and a high-speed, stepping motor unit. I’ll discuss my autofocus results in the Performance section below but, for now, I’ll just say I’ve tried this AF tech in other Tamron lenses, and it’s been solid. I also liked that the lens is compatible with some of the great AF features Sony builds into its mirrorless cameras including Fast Hybrid AF and Eye AF.

Test photo 2 for Tamron 17-70mm lens review
Shooting with the Tamron lens at 17mm, which is equivalent to 25mm on the APS-C sensor-based Sony A6600, I was able to capture the full length of this covered bridge…and then some.

Performance & Image Quality

Optically speaking, the Tamron 17-70mm F/2.8 Di III-A VC RXD features 16 elements in 12 groups. There are two GM (Glass Molded Aspherical) lens elements and one hybrid aspherical lens element. That’s a pretty impressive set for a zoom lens with a constant f/2.8 aperture that retails for under $800.

I mainly shot outdoor photos in the dead of winter while testing the Tamron 17-70mm F/2.8 Di III-A VC RXD, so there wasn’t much wildlife to capture nor were there any sports to challenge the lens’ autofocus. I did, however, test the lens’ RXD AF out while photographing passing cars and it was as reliable as I remember it.

The Tamron 17-70mm F/2.8 Di III is a fast-focusing lens through the entire zoom range, and there was very little to no focus hunting before it locked in. Even when I quickly shifted the lens from 17mm for a wide angle shot and then to 70mm to zero in on a moving vehicle, the lens took a split second to find focus. For casual everyday shooting and travel photography, which is really what this lens is designed for, the AF is more than fast enough.

Test photo 3 for Tamron 17-70mm lens review

Test photo 3 and 4 for Tamron 17-70mm lens review
These two images show the versatile range of the Tamron 17-70mm F/2.8 Di III-A VC RXD. The top shot is captured at 66mm (99mm equivalent) and the bottom is at 17mm (25mm equivalent). It was a cold day, but I had no problem adjusting the focal length of the lens while shooting with gloves on.

Along with being compatible with the Sony A6600’s excellent Fast Hybrid AF and Eye AF, I appreciated the close working distance capability of the Tamron 17-70mm F/2.8 Di III, which can focus as close as 7.5 inches at 17mm and 15.4 inches at 70mm. While I wouldn’t recommend it for extreme macro work, it’s ideal for capturing foreground elements for landscape photos, or for portraits while selectively blurring out the background thanks to the f/2.8 aperture. Focusing is also smooth and quiet, which makes it ideal for video shooting as well.

Image quality was excellent with better-than-average sharpness even when shooting wide open. In my testing, I found the Tamron 17-70mm F/2.8 Di III to be sharpest at f/5.6. Tamron’s tried-and-true VC image stabilizer performed well in reducing camera shake, which came in handy during my outdoor testing in shivering cold temperatures.

My only gripe was visible softness in the corners and some issues with vignetting when shooting at 17mm. Those, however, are relatively minor quibbles for a zoom with so much versatility at a fairly reasonable price point.



Tamron has brought pro-level features and image quality to a compact and lightweight optical package with the 17-70mm F/2.8 Di III-A VC RXD lens for Sony E-mount cameras. Even if you’ve gone completely full-frame with your gear, this APS-C-oriented zoom lens with its constant f/2.8 aperture could make you consider adding the Tamron 17-70mm F/2.8 Di III and a model like the Sony A6600 to your bag. This compact Tamron lens and Sony camera combo really packs a one-two punch.

Check the price of the Tamron 17-70mm F/2.8 Di III-A VC RXD at B&H

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