The Tamron 17-70mm F2.8 Di III-A VC RXD ($799.99) is an exciting lens for photographers using Sony’s APS-C camera system. It delivers the premium optics you expect from an F2.8 zoom, along with speedy focus and an all-weather build, for fewer dollars than Sony’s high-end E 16-55mm F2.8 G ($1,399.99). The 17-70mm skips on-lens controls, but does include optical stabilization. It’s a stunning performer all around and a good enough value to earn our Editors’ Choice award, even if it’s a bit large to pair with Sony’s smaller cameras.
Made for APS-C
Sony’s full-frame a7 camera series garners a lot of attention and is quite popular among pro photographers, but the company offers lower cost APS-C sensor models, too. Cameras like the a6100 and a6400 are lighter and more affordable than full-frame options, but still benefit from quality lenses.
If you’re using a basic starter lens like the E 16-50mm or the discontinued E 18-55mm, an F2.8 zoom like the 17-70mm or Sony E 16-55mm is a serious upgrade. You’ll net notably sharper results and make photos with blurred backgrounds, getting you just a little bit closer to the full-frame look.
The Tamron lens sports a longer zoom range than the Sony E 16-55mm F2.8, but is also a little bigger all around. The 17-70mm F2.8 measures 4.7 by 2.9 inches (HD) at its shortest setting and weighs about 1.2 pounds. The E 16-55mm is a few ounces lighter and takes up a little less room in your bag, at 3.9 by 2.9 inches. Both lenses extend as you zoom in.
It’s definitely on the large side for APS-C cameras. I paired it with an older Sony camera, the NEX-6, and found the lens to be just a little bit too much for the camera. The NEX-6 has a pretty shallow handgrip, and newer bodies like the a6400 pair a bit better with bigger lenses. Even so, the 17-70mm feels more natural on a larger, full-frame camera.
The 17-70mm may cut cost versus the Sony, but there’s no telling from holding it. The barrel is a polycarbonate material with a matte finish, and the lens includes full dust and splash protection to better pair with a6500 and a6600 models. The front element includes an anti-smudge fluorine coat, and the included lens hood adds a bit more protection. A 67mm filter thread is included if you’re interested in adding a protective filter.
Tamron does limit the on-lens controls. The basic zoom and focus rings are there, but that’s it. Spending more on the Sony lens adds a function button and AF/MF toggle switch. Will you miss them? It depends on how you work—I very rarely, if ever, take advantage of on-lens function buttons, but missed having a focus toggle switch here.
The autofocus here is speedy and works with all of your camera’s tracking, face, and eye detection features just as well as a Sony lens. Focus breathing, the effect where the angle of view shifts along with focus, is minimal—if you’re happy with autofocus, this is a good lens for video as well as stills.
Manual focus is less enjoyable. The focus ring turns easily, and while its surface has ridges, it’s not rubberized, and just not the most comfortable to operate. Response changes based on how quickly you turn the ring, but there’s just not quite enough resistance to net a consistent response. If you want to focus manually, the E 16-55mm F2.8 G is worth the premium—its response is linear, and its focus control ring is just more pleasant to use.
The minimum focus distance changes along with the focal length. The lens focuses closest at its widest angle, 7.5 inches from the sensor, for 1:4.8 life-size reproduction. When zoomed to 70mm, you’ll need to pull a little further back, but you can net nearly as large projection at the minimum focus distance (1:5.2). This gives you some creative flexibility—you can shoot wide close-ups for images with more dramatic perspective, or farther back if you’re going for a more natural look.
Optical stabilization is included, Tamron calls it Vibration Compensation (VC). It’s an important feature if you own a Sony camera without IBIS, and to date the a6500 and a6600 are the only APS-C models to include it. With an older NEX-6, I netted blur-free handheld shots at speeds as long as 1/5-second, and stretched it a little further to 1/4-second with the a7R IV, a full-frame that also stabilizes its sensor.
In the Lab
While I pulled out and dusted off an old NEX-6 for product photography and to see how the lens handled on an APS-C body, I spent most of my time using it along with the full-frame a7R IV. Its 60MP sensor automatically crops photos to APS-C dimensions, netting output resolution around 26MP, just a little bit more than the current generation 24MP cameras in Sony’s APS-C family.
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I have no complaints about resolution. I used Imatest to check performance at 17mm, 43mm, and 70mm, and the lens nets resolution as good as you can expect from a 26MP photo, around 3,000 lines, results that are simply outstanding from f/2.8 through f/11.
Diffraction softens images slightly at f/16, but results are still very good (2,600 lines). You’ll net better looking sunstars here, though, with defined points. Resolution drops off noticeably at the minimum f/22 setting, but you do get the best sunstars there.
The 9-blade rounded aperture does its job keeping defocused highlights rounded when the aperture is narrowed, but the lens does show a cat’s eye effect toward the edges of the frame at f/2.8—it’s pretty moderate, though. We do see some onion ring effects in defocused highlights. It’s a distracting look that can busy some backgrounds, but won’t be noticed in every image.
I did note a little bit of flare when working with very strong backlight. It’s a fairly soft, ethereal effect at wide apertures, but can get a little ugly when you’re stopped down for sunstars. If you’re a big fan of backlit portraits you may take pause, but use the hood and don’t shoot directly into the sun (or similarly bright point of light) and you’ll be fine.
In-camera corrections remove distortion and compensate for a vignette. If you turn them off you’ll see barrel distortion on the wide end, the pincushion effect when zoomed in, and dimmed corners at f/2.8. If you use Raw capture you’ll need to apply a profile correction—Adobe Lightroom already has one available for the lens. Either way, you’re just an automatic setting or a couple of clicks away from photos with straight lines and even illumination.
A Lens for Aspiring Photographers
The Tamron 17-70mm F2.8 Di III-A VC RXD is a welcome addition to the E-mount lens library. It betters the premium E 16-55mm F2.8 G in zoom power, adds optical stabilization, and nets exceedingly sharp photos across its zoom range. That it costs a few hundred dollars less than the premium Sony model only adds to its appeal.
It falls a little shy of perfection. Netting the longer zoom ratio and adding stabilization means it’s a bit bigger all around than the E 16-55mm F2.8 G, and the Tamron lens drops the on-lens controls you get with the Sony. You get a bit more flare with the 17-70mm, and the manual focus experience isn’t great.
Still, there’s a lot more here to like than to not. The 17-70mm F2.8 is in a different class than basic kit zooms like the E 16-50mm and E 18-55mm, and it gathers more light than Sony’s quality midrange kit zoom, the E 18-135mm F3.5-5.6. It’s an especially appealing lens for photographers who’ve grown out of bundled kit zoom, and a worthy Editors’ Choice winner.
