Tamron 17-70mm E at BHphoto, Adorama, Focuscamera, Calumet Germany and Wex UK.
The lens got tested by Lenstip. The conclusion is:
Let’s discuss the price first. The tested Tamron is available in shops for about $800, the same as the Fujinon 16-80 mm f/4.0, by 1 EV slower. The Nikkor 16-80 mm f/2.8-4.0, a veteran lens on the market, is about $267 more expensive. The Sigma 17-70 mm is the best option from the financial point of view as it can be bought for a sum of $500. Still, taking into account unique parameters of the Tamron, the fact that you deal here with a novelty lens rivalled only by older instruments, present on the market for several years already, it seems the Tamron is priced very well. Of course it cannot be called cheap but, taking into account the current situation, you can say lenses of this class and with such parameters have similar price tags.
The constructors of the Tamron 17–70 mm f/2.8 Di III-A VC RXD faced a really difficult task. Every time a producer tries to offer something unique, a product no other manufacturer features, the bar is set very high, higher than usual. It’s nothing strange that slip-ups, like in this case are bound to happen because it is really difficult to guarantee low vignetting and good performance against bright light in a construction of such a type. Anyway the mistakes are present and you can complain as long as you like – you have very good reasons to do so.
However, this lens managed to achieve the most important task: despite a very large and very universal focal range combined with a good, fixed f/2.8 aperture fastness, it guarantees a very good image quality across the frame, no matter what focal length you employ. It seems the tested Tamron performs even a tad better than you would expect, and, as such, it fully deserves a very high final assessment it got.
