Review by Klaus Schroiff, published June 2007

Lens kindly provided by Tamron Europe!

Introduction

In absolute terms the Tamron is a fairly big lens but within its class it is actually comparatively compact and light-weight. Fortunately the weight reduction measurement don't seem to come at cost of build quality - it is obviously a pretty sturdy lens also thanks to an IF design and a constant physical length regardless of the focus setting. The very broad, rubberized focus ring operates very smooth. An quite nice feature is FEC (Filter Effect Control), a dedicated control ring to rotate the filter thread even with attached lens hood - a quite interesting and efficient approach.

The lens has no internal AF motor and relies on a slotted drive screw operated by the camera. This generates some noise during AF operations and the AF speed is very slow when focusing throughout the extensive focus range. This can happen quite frequently because Tamron did not implement a focus limiter - in the middle of focus nowhere there's a good chance that the AF focuses towards the wrong direction before hunting back again. If the focus is well off it makes sense to do a coarse manual pre-focusing prior of activating the AF. You change between AF and MF by pushing/pulling the focus ring so there's no need to fiddle around with the small AF/MF switch on the camera. A side effect of this focus clutch design is the decoupling of the focus ring from the AF gears so it does not rotate in AF mode.