Review by Markus Stamm and Klaus Schroiff, published November 2010

Special thanks to Andrea Halter for providing the lens!

Introduction

This leaves this segment open to third party offerings. Sigma brought their OS ("Optical Stabilizer") to a number of lenses and Tamron was next in line with their VC ("Vibration Compensation").
Tamron first introduced VC in their lineup of extreme zoom lenses - the Tamron AF 18-270mm f/3.5-6.3 VC and AF 28-300mm f/3.5-6.3 VC. Regarding their sales volume these are their key lenses so they seem to be pretty much convinced that their VC system is ready for prime time. The Tamron AF 17-50mm f/2.8 SP XR Di II LD Aspherical [IF] VC reviewed here is even more ambitious because large aperture stabilized lenses are even less forgiving with respect to quality control issues (VC/VR is technically nothing else but a controlled decentering). The pricing is very competitive at around 400EUR/550US$.

The build quality is typical for a consumer grade zoom lens although Tamron SP ("Super Performance") lenses are actually intended to target the high end market. Most of the lens is made of good quality plastics based on a metal mount. The zoom ring operates quite smoothly. The focus ring has only a very short focus path so accurate manual focusing is a bit on the difficult side. It is somewhat anachronistic that the focus ring still rotates in AF mode - neither Canon USM nor Sigma HSM lenses show this effect anymore. The lens extends when zooming towards the long end of the zoom range and the supplied petal-shaped hood adds a little extra length. Thanks to internal focusing, the front element does not rotate so using a polarizer remains easily possible. The lens is quite a bit bigger compared to its non-VC sister lens although still a lot smaller than the rather huge Nikon AF-S 17-55/2.8.

The Tamron AF 17-50mm f/2.8 VC still relies on a conventional AF micro-motor (which makes it compatible also with the entry level Nikon DSLRs). Speed-wise this is not a problem because of the already mentioned short focus path (turning the focus ring by a ~40 degrees traverses the whole focus range) but AF operations are noticeable (noise-wise). The AF accuracy was ok and not an issue in the field with our test DSLR.
Regarding the VC Tamron claims an efficiency of up to 4 f-stops. While we can confirm that the VC works very well, we recommend avoiding to exploit this to the max due to the increasing number of outliers in field conditions.