Tamron AF 28-75mm F2.8 Di III RXD

The Tamron AF 28-75mm F/2.8 Di III RXD is a new lens for Sony E mount cameras. Not only is it the first zoom lens for E mount from a third party manufacturer, it is also a completely new design exclusive for mirrorless full frame cameras.

Technical specs:

  • Focal length range: 28 – 75mm
  • Angle of view: 75° to 21°
  • Max. aperture: F2.8
  • Aperture blades: 9 (rounded)
  • Optical design: 15 elements in 12 groups
  • Min. focus distance: 19cm (wide) to 39cm (tele)
  • Max. magnification ratio: 1:29 (tele) to 1:4 (wide)
  • Filter size: 67mm
  • Dimensions: ~7.3 x 11.8cm
  • Weight: 550g

The Tamron 28-75mm F2.8 RXD was released a month ago and is available for ~800€. The price tag is really fair when compared to the other options for Sony mirrorless and some reviewers even call it a bargain. However, in my opinion 800€ is still a lot of money for a standard zoom lens when compared to similar offers in the Canon or Nikon department (e.g. the Tamron 28-75mm SP lens costs about half).

The lens comes in a rather spartan and uninspiring packaging. Included in the box – apart from the lens obviously – are only the lens caps and a lens hood.

 

Build quality

The Tamron 28-75mm is made of plastic, except for the mount which is metal. The barrel has a smooth finish while the focus and zoom ring have a texture and are rubberized. The focus ring is very smooth, the zoom is a bit firmer which should prevent lens creep.

plastic barrel, metal mount

Build quality seems fair, everything is firm, there are no loose parts or gaps and the lens looks nice. However, it feels quite cheap due to the used materials. I would say it is no better than a kit zoom and certainly does not resemble an 800€ lens. There is even a molding seam visible.

molding seam

Maybe Tamron decided to use plastic instead of metal to save weight. But then again there are plenty of lightweight lenses out there with a metal barrel (e.g. Zeiss Batis line). In fact, most Sony lenses for mirrorless cameras are made of metal (even some of the cheap kit zooms).

metal mount with rubber gasket

Fortunately, the Tamron 28-75mm has a rubber gasket at the mount and is fully weathersealed (although I wouldn’t put much confidence in that).

Mechanical quality rating: 6/10

 

Features & versatility

One of the strongsuits of this Tamron lens is versatility. Apart from the useful focal range of 28 to 75mm, it also shines with exceptional close-focus capabilities. The maximum magnification ratio is 1:4, which brings it into macro territory.

Apart from that, the constant max. aperture of F2.8 throughout the focal range allows to use this lens in dim lighting situations or create some nice background blur (e.g. for portraits). Also video makers will appreciate the constant aperture. The lens also seems to be almost parafocal, so the subject stays in focus without readjusting the focus when you zoom in or our.
The focus is internal and silent, with minimal breathing. Manual focus is smooth and easy despite being focus by wire. Autofocus speed is good but nothing to get excited about, maybe a bit slower than on Sony lenses.

Another welcome feature is the fluorine coating of the front lens element, which helps to repell water, oil and dirt. In combination with the weather sealing this should make the lens perfectly suitable for the outdoors.

fully extended at 75mm

When zooming in to 75mm, the lens extends by about 1 inch. The zoom ring is rubberized and therefore easily attracts dirt.

mounted on the Sony A7 III

Although awkwardly long, the lens is lightweight and feels well balanced on my Sony A7 III. It might be worth mentioning that the zoom ring is at the front of the lens while the focus ring is closer to the mount. For some this could be an issue since on most other zoom lenses it is the other way around. I got used to it pretty quickly, so for me not an issue at all.

So what is missing? Well, there are no buttons or switches on the lens (e.g for MF/AF or focus hold). Also, the lens does not offer optical image stabilization, which is problematic if your camera body does not offer in-body stabilization.

Features & versatility rating: 9/10

 

Image quality

Center and corner sharpness at different apertures, first at 28mm:

28mm, center and corner crops (right click -> ‘open in new tab’ to see higher resolution)

 

While the center sharpness is excellent right from F2.8, the corners are a bit washed out and need stopping down to F8 to become acceptably sharp. Let’s have a look at 50mm and 75mm:

50mm, center and corner crops (right click -> ‘open in new tab’ to see higher resolution)

 

Situation is actually very similar at 50 and 75mm. If you need sharp corners, you need to stop down to at least F8. Overall a very good result for a standard zoom.

Close focus image quality is quite impressive:

28mm F2.8, close focus
center crop from the photo above

 

28mm F2.8, close focus
crop from photo above

 

75mm F2.8, close focus
crop from the photo above

 

Macro: As mentioned before, the max. magnification ratio that you can achieve with this lens is 1:4. That is just enough to inspect the subpixel layout of a standard PC monitor:

subpixel layout of a PC monitor

 

Distortion: As expected, there is barrel distortion at the wide end and a pincushion distortion at the long end. Currently, distortion is not corrected in the out-of-camera JPEGs, i.e. it looks exactly the same as in the RAW files.

uncorrected RAW shows barrel distortion and vignetting at 28mm F2.8

Vignetting is visible, but still acceptable for such a lens.

Laterial chromatic aberration is very low, but can be spotted in unedited RAW files. It is well corrected in the JPEGs as shown below (crop from the left border).

 

Bokeh fringing (LoCA) is visible, but reasonably well controlled.

LoCA at F2.8
crop from photo above

 

Bokeh: As expected, the bokeh quality isn’t quite comparable to a prime lens. The background blur but tends to get a bit busy and distracting, but still ok for a standard zoom.

bokeh at 75mm F.8
bokeh at 28mm F2.8
crop from photo above (top edge): slightly nervous, almost artistic bokeh

Wide open, the bokeh balls are relatively homogeneous with only minimal onion rings. When stopped down, the onion rings become more apparent. Also, the bokeh balls can sometimes appear slightly doughnut shaped (pronounced outline).

bokeh ball at 28mm F2.8, not perfectly round due to vignetting of the diaphragm
bokeh ball at 75mm F2.8

 

Optical quality rating: 7/10

 

Comparison vs other Sony FE standard zooms

The Tamron is optically clearly better than the Sony FE 28-70mm F3.5-F5.6 or the Sony Zeiss 24-70mm F4, but according to other reviewers not quite as good as the much bigger and 3x more expensive Sony 24-70mm F2.8 GM lens. The Tamron seems to be just about on par with the Sony 24-105mm F4, which is therefore one of its closest rivals. The Sony covers a larger focal range and has a premium build quality, but is also one stop slower, slightly bulkier, heavier and about 50% more expensive.

 

Summary

Positive:

  • lightweight
  • excellent sharpness in the center at all apertures
  • good sharpness at the edges from F5.6 (corners need F8)
  • low lateral and axial CA
  • quiet and fast AF
  • excellent close-focus capabilities
  • weathersealed and with fluorine coating
  • small filter diameter of just 67mm
  • 10 years of warranty (region specific)

Neutral:

  • 24mm on the wide end would have been nice
  • no optical image stabilization
  • no buttons or switches on the lens
  • distortion at 28 and 75mm is not great, but not too bad either
  • vignetting is noticable

Negative:

  • subpar materials (plastic fantastic)
  • corner sharpness below F8 is only acceptable
  • inconsistent bokeh quality
  • awkwardly long

Conclusion: Overall, the Tamron 28-75mm is a great standard zoom for Sony E mount, with solid optical performance and outstanding versatility. Due to its size and weight, it is perfectly suitable for traveling. I just wish the lens had a more premium build quality.

Rating:  7.5/10    highly recommended!

Value:  7/10    (at 800€)

You can buy this lens e.g. from Amazon.de, B&H or digifuchs.ch.

 

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