Tamron AF 17-50mm f/2.8 SP XR Di II LD Aspherical [IF] (Nikon) - Review / Test Report
Lens Reviews - Nikon / Nikkor (APS-C)

Review by Klaus Schroiff, published July 2006

Special thanks to Peter Poete for providing this lens!


The Tamron AF 17-50mm f/2.8 SP XR Di II LD Aspherical [IF] is the latest addition to the popular set of fast standard zooms. Tamron has categorized the 17-50mm as SP (Super Performance) lens - Tamron's professional grade product league. As indicated by the Di II the lens provides a reduced image circle so it is only compatible to APS-C DSLR (tested on the D200). Its field-of-view is equivalent to ~25.5-75mm (1.5x crop) on full frame cameras. The lens is available in Canon, Nikon and Sony (KM) mount. At a price around 400€/US$ the Tamron costs only a fraction of the genuine manufacturer alternatives making it pretty attractive to budget shoppers who are looking for a good deal for their bucks.

(the image shows the Canon EOS variant of the lens)

The build quality is very decent but typical for most Tamron lenses there's a little too much plastic in there for my taste. Nonetheless it is still one of the better implementations in Tamron land. The zoom ring feels very smooth. Same goes for the focus ring which is even a little damped.
As you can see in the product shot above the lens extends when zooming towards the long end of the zoom range and the supplied petal-shaped hood adds a little extra length on top. Thanks to internal focusing the front element does not rotate so using a polarizer remains easily possible.
The lens has no internal AF motor and relies on a slotted drive screw operated by the camera. However, due to a very short focus path (about 45 degrees) the the AF is very fast. AF accuracy wasn't overly impressive on the D200.

Equiv. focal length25.5-82.5 mm (full format equivalent)
Equiv. aperturef/4.2 (full format equivalent, in terms of depth-of-field)
Optical construction16 elements in 13 groups inc. 2 hybrid aspherical elements, 1 LD (Low Dispersion) glass element, 1 XR (Extra Refractive) element
Number of aperture blades7 (rounded)
min. focus distance0.27 m (max. magnification ratio ~1:4.5)
Dimensions82 x 74 mm
Weight434 g
Filter size67 mm (non-rotating)
Hoodsupplied, petal-shaped
Other features-

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