|Tamron 17-28mm f/2.8|
|Lens Mount||Sony E-Mount (Full Frame)|
|Maximum Aperture||f/2.8 Constant|
|Weather Seal||Moisture-Resistant, Dust-Resistant|
|Aperture Blade||9, Rounded|
|Autofocus||RXD stepping motor|
|Optical Design||13 Elements in 11 Groups|
|Minimum Focus Distance||19 cm|
|Dimensions||73 x 99 mm|
Build Quality / Design
Build quality of the Tamron 17-28 f/2.8 is very similar to the Tamron 28-75. It is mostly made of high quality plastic. Despite feeling a bit plasticky, the quality is very nice. There are no switches or buttons on the lens. The zoom and focus rings both feel smooth and nice.
The good thing about it’s plastic construction is that the lens is very light at only 420g, which is ridiculously light for a wide angle f/2.8 zoom lens.
The front filter thread is only 67mm which is the same size as the Tamron 28-75mm f/2.8 which allows uses with both lenses to share filter between the two lenses. But whether the small front filter thread would cause severe vignetting? We will have a look later in this review.
To see how sharp the lens is at various focal length, I’ve tested the lens at three focal length: 17mm, 22mm and 28mm.
Centre sharpness is excellent at all these focal length. Even at maximum aperture f/2.8, the sharpness is already really good.
Corner sharpness is very good at 17mm. Even at f/2.8 the sharpness is good enough for me on 24MP output.
At 22mm, the corners are a bit softer. Stop down to f/4 it is sharper but stop down to f/5.6 then sharpness becomes very sharp.
The corner sharpness improves at 27mm. While it is still a bit soft at f/2.8, stop down to f/4 would already result in much sharper corners.
Overall, I think Tamron did a very good job in maintaining the sharpness across the focal length range and from center to edges yet managed to keep the size of the lens very compact.
With the small 67mm front filter thread, I was a bit worried if the vignetting could be quite severe. Fortunately this is not really the case.
At 17mm, there is some noticeable vignetting when shooting at f/2.8. Vignetting reduce a bit at f/4 and at f/5.6 vignetting is not really noticeable anymore.
At 28mm, there is a lot less vignetting even at f/2.8. At f/4 vignetting is almost completely gone.
The amount of vignetting is definitely better than what I would have expected from such a compact wide angle lens.
Lens Flare and Chromatic Aberration
Lens flare is very well controlled. Shooting into the run, or shooting a bright light source at night results in very minimal amount of flare and ghosting.
Chromatic aberration is also really well controlled. Checking the backlit scene of all my photos and I see very very little amount of chromatic aberration. Even around the high contrast area I see very little amount of colour fringing even when I was checking the photo at 100% zoom.
For a wide angle lens, bokeh is probably one of the least important thing in terms of image quality. But you can dissolve the background into bokeh when shooting objects at very close distance.
The bokeh from the Tamron 17-28mm f/2.8 is round and not too nervous. However when checked closely, I noticed bokeh has some sign of onion ring pattern. Not very strong but it’s noticeable when you zoom in and check the photos closely.
A lot of ultra wide angle zoom lenses have bad distortion, unfortunately the Tamron 17-28 f/2.8 is the same. There are some distortion from 17mm to 28mm.
Lens design is always a balance between various compromises. Size, Speed, Price, Focal length range. Tamron obviously chose to create a compact fast constant f/2.8 lens with very reasonable price. So they got the speed, price and as you can see from my test results very decent image quality as well. That explains why the focal length is only 17-28mm instead of going wider or covers a bigger range.
While I would certainly love to see if the lens can go a bit wider, I also really love the really compact size and light weight of this lens. The lens really feels more like a f/4 zoom lens than a f/2.8 zoom lens in terms of size and weight. If you already have a Tamron 28-75 f/2.8 in your camera bag, the Tamron 17-28 f/2.8 would be the perfect companion for your standard zoom lens.