Tamron 28-75mm f/2.8 Di III RXD Review

Tamron wasn't the first third-party to release an autofocus lens for Sony's full-frame mirrorless camera system—it was beaten to the punch by the likes of Rokinon and Zeiss.

But the 28-75mm f/2.8 Di III RXD ($799) is the first third-party zoom lens we've seen for the system.

It's getting a lot of buzz from photographers using Sony gear, and with good reason.

It's a full stop brighter than the Zeiss Vario-Tessar T* FE 24-70mm F4 ZA OSS, and a heck of a lot more affordable than the premium $2,200 24-70mm F2.8 GM.

Its image quality isn't impeccable, but it's pretty darn good when you consider its price, size, and f-stop.

If you don't have the budget for a premium G Master lens from Sony, this is a fine, affordable alternative, and an Editors' Choice.

Design: Basic Black

The 28-75mm ($879.00 at Amazon) isn't a head-turner.

The svelte zoom—measuring 4.6 by 2.9 inches (HW), weighs 1.2 pounds, and supports 67mm front filters—covers a 28-75mm range.

It's at its shortest at 28mm, as it extends when zoomed in.

It doesn't have quite the wide-angle coverage as Sony's pair of 24-70mm zooms, which can be a turn-off to wedding photographers, who tend to need to shoot a little bit wider to capture groups reveling at the reception, or all the architectural details of cavernous cathedrals.

The barrel is black polycarbonate with a rubberized zoom ring at its front and a bare polycarbonate manual focus ring occupying the middle.

A reversible lens hood is included, as well as front and rear caps, but you don't get any sort of storage case or pouch.

There are no control switches or toggles on the lens itself—you'll adjust focus mode via camera settings and there is no in-lens stabilization to enable or disable.

The lack of optical stabilization isn't a huge deal unless you're shooting with a first-generation a7 model.

The II and III series, as well as the a9, all include in-body five-axis stabilization.

It's very effective for still photography and does a good job with video too.

I noticed some shake in handheld 4K footage shot at 75mm near the macro focusing limit of the lens, but the higher magnification capture is more strenuous on a stabilization system.

Other handheld clips looked just as good as with any other lens paired with the a7R III.

The first copies of the 28-75mm to arrive at retail were victims of a firmware bug that caused occasional issues with autofocus when recording video.

This was fixed via a firmware update.

I didn't get a chance to apply the update myself—Tamron updated the lens before sending it over.

If you procure an early shipping copy of the lens without the firmware update (at press time, the current version is identified as Ver.

02 in the camera menu), you can apply the fix yourself with just a memory card and camera—assuming you aren't using macOS 10.13 (High Sierra).

The update software works with Windows 7 SP1, Windows 8.1, and Windows 10, as well as macOS 10.10 (Yosemite) through 10.12 (Sierra).

Despite not supporting the latest macOS, having the ability to upgrade lens firmware without the need for additional hardware is a big plus.

If you buy a Tamron SLR lens you'll need the TAP-in Console accessory to do so.

Unlike some other third-party lenses, the 28-75mm supports all of Sony's focus modes.

With the a7R III I had no problems with EyeAF and face detection, and the lens woks perfectly fine when tracking moving subjects.

All of Sony's full-frame cameras incorporate weather sealing.

The 28-75mm is also sealed, with six internal seals to prevent moisture from getting into your camera.

Typically we see this hand-in-hand with dust protection, but Tamron makes no claim with the 28-75mm.

It does include fluorine coating in the design.

The front lens element is protected with the material, which repels dust and grease.

So it's not only easier to clean than lenses without fluorine, it's also less prone to picking up smudges.

Close focus distance varies based on the zoom setting.

Its design allows for the closest focus—7.5 inches—at the 28mm position, which nets macro magnification of 1:2.9 life-size.

When set at 75mm you'll need to back up a bit, to 15.3 inches, for 1:4 macro capture.

It's better than both 24-70mm Sony zooms—the pricey G Master nets 1:4.2 at 70mm and the 24-70mm F4 ZA tops out at 1:5 magnification.

Image Quality: Mostly Excellent

I tested the 28-75mm with the 42MP a7R III, currently the highest resolution model available from Sony.

Even when paired with a demanding sensor, it puts up strong resolution numbers in our Imatest evaluations—for the most part.

The 28-75mm shows its overall weakest performance at the wide angle setting.

At 28mm f/2.8 it scores 2,814 on a center-weighted evaluation, which does past muster for sharpness, but just barely, and not evenly across the frame.

The central area is tack sharp, at 4,278 lines, but it gets softer as you move away from the center.

The mid parts of the frame show just 1,810 lines, and the outer edges dip to 1,431 lines.

If you're working up close and blurring out the background around a mostly centered subject you'll love the results the lens delivers, but landscape shooters will want to stop down to net strong results from center to edge.

See How We Test Digital Cameras

At f/4 the crisp area of the frame expands noticeably.

The average score climbs up to excellent territory, at 3,717 lines.

The central area is outstanding, topping 4,800 lines.

The mid parts are acceptable, 2,919 lines, though not off the charts.

Edges are still a bit soft (1,725 lines), but that is not out of the ordinary for a lens of this type.

Even Sony's premium 24-70mm G Master shows soft edges at wider apertures when shot at 24mm.

Things are better at f/5.6, with 4,103 lines averaged across the frame, mid parts that top 3,700 lines, and edges that, while not great, show a only sightly soft 2,294 lines.

At f/8 the average score is 4,289 lines, and most of the frame scores better than 4,000 lines.

Edges still lag behind, but at 3,269 lines, you won't find much wrong with them.

Landscape shooters will find f/11 to be the sweet spot for resolution, the f-stop at which the lens puts up the highest resolution at 28mm from edge to edge.

The average is a little less than you get at f/8 (4,182 lines), but performance is outstanding right up to the edges of the frame, which show 3,903 lines.

We start seeing the effects of diffraction at f/16, where the average score drops to 3,793 lines.

It's more of an issue at f/22.

You get just 2,894 lines when stopped down to the minimum aperture.

The performance issues we saw at 28mm f/2.8 are gone at the 50mm zoom position.

At f/2.8 the lens shows 3,773 lines here, with edges that top 3,100.

There's an improvement at f/4—the average score is 4,250 lines, again with the sharpest part of the frame at the center and excellent mid part (3,898) and edge performance (3,781 lines).

That holds up as you stop down further.

At f/5.6 we see 4,410 lines, and resolution peaks at f/8 (4,405 lines).

You still get strong image quality at f/11 (4,165 lines), though you'll lose something shooting at f/16 (3,767 lines) and f/22 (2,884 lines).

At the 75mm position the resolution drops off a bit.

At f/2.8 the lens resolves 3,273 lines on average, but as with 28mm, we see some softness at the mid parts (2,508 lines) and edges (1,975 lines). Performance is stronger at f/4, with the average score climbing to 3,635 lines.

Resolution in the mid parts of the frame is much better (3,284 lines), and while the edges are still a bit soft at 2,343 lines, they aren't blurry.

At f/5.6 the image is sharp from center to edge, although we still see less resolution at the periphery.

Edges show a strong 3,059 lines, while the crisper performance at the center and mid parts brings the average up to 4,051 lines.

Things are better across the frame (4,196 lines) and at the edges (3,474 lines) at f/8.

If you're shooting portraits at f/2.8 or f/4, edge performance doesn't mean much at 75mm—typically the frame will be blurred by depth of field there anyway.

If you like shooting landscapes at moderate telephoto distances, f/11 will net you the best performance from center to edge.

The average score is almost as good as the lens gets (4,159 lines), and edges top 3,800 lines.

As with other focal lengths, try to skip f/16 (3,798 lines) and f/22 (3,059 lines).

It's not all about resolution.

We also take a look at distortion when evaluating lenses, as well as how even light is cast on the sensor—most lenses are brighter at the center than at the corners.

At 28mm we see about 2.5 barrel distortion, an effect that causes straight lines to be drawn with an outward curve.

It gives way to pincushion distortion as you zoom in.

We see a barely noticeable 1 percent at 50mm and a more pronounced 1.5 percent at 75mm.

The pincushion effect causes straight lines to appear with a slight inward bulge.

This is something that can be compensated for in software.

Take a look at the image above, shot at 28mm with no corrections applied, compared with the shot below, which has had distortion removed using Lightroom's lens profile for the 28-75mm.

You lose a little bit of the scene by removing barrel distortion, but the lines of the sidewalk and wall appear as they do in reality in the corrected image.

You'll also notice that the corners of the corrected image are also a bit brighter.

The 28-75mm casts a bit of a vignette, though it does vary based on the aperture and focal length.

At 28mm f/2.8 corners lag behind the center by -4EV.

Stopping down to f/4 cuts the deficit to -2.8EV, and we see a -2EV drop at f/5.6.

At narrower f-stops the vignette is negligible.

If you shoot JPGs you can enable in-camera correction, and while the lens still has a bit of corner dimness at f/2.8 (-2.1EV) with it enabled, it's not a big problem at narrower settings.

At 50mm we see -1.9EV at f/2.8 when shooting in Raw format.

At smaller f-stops the vignette isn't an issue, and if you enable in-camera corrections for JPG shooting you'll see a barely noticeable -1.2E drop at f/2.8.

The corners are dimmer at 75mm.

At f/2.8 the deficit is -3.7EV, which is cut to -2.4EV at f/4 and an almost negligible -1.4EV at f/5.6.

JPG shooters will deal with -1.9EV at f/2.8, but at f/4 and beyond the vignette isn't apparent in most scenes.

An Excellent, Affordable f/2.8 Zoom

There are certain size and weight advantages to designing mirrorless cameras—getting rid of the mirror and optical viewfinder reduces the amount of moving parts, and allows for very short distances between the lens mount and sensor.

The modern mirrorless revolution started with a smaller sensor format—Micro Four Thirds—which allows for some seriously tiny lenses.

But as we've put larger and larger sensors into mirrorless bodies, it's been clear that you can't defeat the laws of physics.

While some lens designs—notably wide-angle zooms like the Soy FE 12-24mm G—are significantly smaller than comparable lenses for SLR systems, the design differences are not as pronounced for many other types of lenses, including standard zooms like the 28-75mm.

Sony opted for a no-compromise design with its f/2.8 standard zoom, the 24-70mm F2.8 GM, a lens that's as large and heavy as similar optics for SLRs.

But you pay for it in a couple ways—a $2,200 price tag and an extra two pounds hanging off the front of your camera.

Tamron took the opposite approach, sacrificing some wide-angle coverage and edge sharpness to bring a compact f/2.8 zoom to market at a price that's more within reach of enthusiasts who simply don't have a couple thousand dollars to spend on a lens.

For me, the approach works.

Not once did I feel limited when shooting with the 28-75mm.

It focuses up close for near macro shots, it's deadly sharp when stopped down a bit, and it's perfectly capable of capturing quality images and video at its widest setting.

If you're a pro working events you'll probably miss being able to use a slightly wider angle, so if you're using your camera to make money, the 24-70mm F2.8 GM is likely a better choice.

But for enthusiasts and pros working in other disciplines, the Tamron represents a big savings in price without a big drop in performance—and earns our Editors' Choice.