Tamron 17-28mm f 2.8 Di III RXD is the second zoom lens released by the Japanese manufacturer for Sony FE. The first was a Tamron 28-75mm f 2.8 RXD III that enjoyed enormous success. To cover all the usual focal lengths, Tamron has also announced a 70-180mm f 2.8 telephoto lens that will be released in 2020. Thus, users of the Sony FE frame will be able to have a full photo kit with constant aperture f 2.8.
At first glance the focal lengths are surprising: 17-28; 28-75; 70-180, as photographers we are used to 16-35; 24-70 and 70-200. After I documented a bit and understood what the logic is, I thought the idea of Tamron was great.
In order to reduce the production costs, but also the dimensions, without sacrificing the optical performance the Japanese reduced the focal range, with which they juggled until they reached a perfect balance maintaining a maximum aperture of 2.8. Of course they were also helped by the physics of the mirorless mounts that allow the construction of lenses that could not be physically built for the DSLR mounts.
- Optics: 13 elements in 11 groups
- Focal distance: 17-28mm
- Maximum aperture: f 2.8
- Aperture blades: 9 rounded
- Minimum focus distance: 0.19m at 17mm
- Dimensions: 73mm x 99mm
- Weight: 420g
The lens body is made of good quality plastic that does not give the impression of a cheap lens. The zoom ring moves smoothly, with a fairly small turn of about 90°. The front element moves behind the filter, as in the Canon 17-40mm L for example, so with a fitted protective filter it acts as an internal zoom. The focus ring moves smoothly, it has no direct mechanical connection as it is a focus by wire type. It is positioned close to the zoom ring, and many times I accidentally rotated it, but being an electronic focus it is not active all the time.
The mount is metallic and protected against moisture with a rubber seal.
Tamron states the lens is weather sealed, which is a big plus.
Another advantage is that it uses 67mm filters.
At just 420g it is well balanced on a body like the Sony a7 III.
It is a very sharp lens starting from f 2.8. At f 4, there is an improvement in the corners. It can proudly stand by his older brother Tamron 28-75mm.
The colors and contrast are excellent, they resemble the vibrant colors of the Canon L series.
The distortions are quite pronounced at 17mm. Somewhere between 19-21mm the distortions disappear, reappearing towards the long end, but not too pronounced.
Being a new lens there is no profile for Lightroom. Strangely, a correction profile is applied in camera, but only for jpeg files. Lightroom sees a profile embedded in the raw files, but does not apply it. Of course, these problems will be solved in the near future.
The lens vignettes quite strongly at f 2.8, at f 4 it is better, and at f 5.6 the problem disappears and we have constant lighting throughout the frame.
Flare and chromatic aberrations
In terms of chromatic aberrations, the lens is very good.
The flare is extremely well controlled, unlike other wide lenses, the front element is small and flat, in combination with the quality treatments of the lenses the results are very good.
At closed apertures, the lens produces 18 rays around the light sources.
I didn’t expect too much at this focal length. The blurred background can be obtained quite easily, however, it is quite crowded. It seems to me that it looks a lot like the big brother’s bokeh, Tamron 28-75.
Of course bokeh is an element of taste.
I chose a crowded background in these tests. I shot at 28 and 17 mm and the images are not processed not to distort the results.
And here the problems start…
When the focus is working properly the focus is extremely fast and completely silent. Tamron 17-28mm f 2.8 Di III RXD is equipped with an extra silent stepping drive motor, same system used on Tamron 28-75mm.
I tested it quite intensely because for me it is important in sports photography. It enjoys all focus modes just like a Sony native lens. The success rate is somewhere around 90% successful shots for moving subjects in good light.
On my body, Sony A7 III with the latest firmware, sometimes the lens does not focus well when the camera goes out of standby. Nothing is in focus because the lens focuses after infinity. The problem disappears if I restart the camera and remount the lens. I sent the lens into service and received another copy instead. Unfortunately, it also suffers from the same behavior.
You can see a video that describes the problem here: https://www.youtube.com/watch?v=HGzRjzeyFos
There are other users on the forums who describe the same behavior.
There are many others who use the lens and do not have this problem, including A7 III.
I hope it will be resolved with a new firmware, as was the case with Tamron 28 75, but Tamron have not officially reported that there would be any problem with the focus for 17 28.
· Great value for money
· Geat image quality
· Small and light
· Weather sealed
· Uses 67mm filters
· Obviously, problems with the focus system
· Small focal range
· No stabilization
Is great for
I recommend it for landscape, travel, astrophotography, concert photography, sports, architecture (but beware of distorsions at the wide end)
As a zoom alternative we have the native Sony 16-35mm f 2.8 GM and 16-35mm f 4 OSS lenses, in addition to these would be Sigma 14-24mm f2.8.
I am glad to see that third party lens manufacturers have realized how important the new mirrorless market is and come up with new optical formulas.
It’s an excellent lens, and I recommend it despite the problem with the focus system. However, check it before you buy it.
I look forward to an official reaction from Tamron.
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