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Review by Markus Stamm and Klaus Schroiff, published June 2011
The Tamron AF 17-50mm f/2.8 SP XR Di II LD Aspherical [IF] has been a huge success for Tamron and is still one of the most attractive standard zoom options for APS-C crop cameras. This is especially true for Nikon users, where the corresponding native Nikkor lens, the AF-S DX 17-55/2.8, is both huge and expensive.
In this review we will have a look at how the lens performs on our current DX test camera, the Nikon D7000.
Tamron has categorized the 17-50mm as a SP (Super Performance) lens which is Tamron's professional grade product league. The lens may be a "pro spec f/2.8" lens but the build quality is not quite up to pro standards since there's quite some plastic used on the lens body. Nonetheless, the overall quality is decent and it is still one of the better implementations in Tamron land.
Both the zoom and focus control rings operate pretty smooth. Unfortunately the latter does rotate during AF operations which is a bit dated approach by now. As you can see in the product shot below 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 seen two versions: the initially released one (product code A16N) has no internal AF motor and relies on a slotted drive screw operated by the camera, a feature that is no longer available on newer entry-level Nikon DX DSLRs. So, on those cameras that model does not provide any AF functionality and needs to be focused manually.
The current version (A16NII), which we review here, features an integrated DC motor that makes the lens compatible with all Nikon DX cameras again. The AF is quite fast (thanks to a rather short focus path), but the motor generates a noticeable amount of noise.
The Tamron is a G-type lenses and does not provide a dedicated aperture ring anymore.
|Equiv. focal length||25.5-75 mm (full format equivalent)|
|Equiv. max. f-stops||f/4.2 (full format equivalent, in terms of depth-of-field - not speed)|
|Optical construction||16 elements in 13 groups inc. 2 hybrid aspherical elements,
1 LD (Low Dispersion) glass element, 1 XR (Extra Refractive) element|
|Number of aperture blades||7 (rounded)|
|min. focus distance||0.27 m (max. magnification ratio ~1:4.5)|
|Dimensions||82 mm x 74 mm|
|Filter size||67 mm (non-rotating)|
|Hood||petal-shaped, bayonet mount (supplied)|
|Other features||Lens reports distance information to camera, integrated DC motor (NII model only)|