3 asferici, 2 a bassa dispersione, 1 a dispersione extra bassa
Camera Labs It’s sharp in the APS-C image-circle and is pretty small and light. So light in fact that both the 17-28mm plus the 28-75mm zooms weigh only 1kg although they offer a constant f2.8 aperture throughout the zoom-range.
ePHOTOzine9.8 The new Tamron 17-28mm f/2.8 Di III RXD performs superbly, feels fantastic to use and is a very reasonable price as well. It's light, efficient, moisture resistant and seems to tick all the boxes. This one easily makes it into the hallowed ranks of an Editor's Choice.
Phillip Reeve [Tested on 42 MP camera] Optically it is very capable at the wide end, a little less so at the long end [...] Stopped down to f/8.0 to f/11 it should be good enough for most applications though [...] Tamron also decided to put some effort into correcting the lens for coma at the wide end [...] Flare resistance is class leading. [...] Bokeh is rather nervous, so this 17-28mm 2.8 could not replace a fast medium wide angle prime environmental portraiture.
Sony Alpha Blog It offers very good/excellent performances at 2,5 times less the price of the Sony FE 16-35 mm F2.8 GM (2700 euros). Obviously the focal range is smaller, but if you have the Tamron 28-75 it complements it without any overlap.
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