Review by Klaus Schroiff, published November 2013

Introduction

The build quality of the Tamron lens is very good but it stays slightly short of what we have seen on the Canon and Sigma side. This is mostly because of the extensive use of plastics in the construction. Technically this is fine, of course, it just feels somewhat less reassuring than the Sigma AF 105mm f/2.8 OS macro or the Canon EF 100mm f/2.8 USM L IS.
There are two major mechanical improvements compared to the old Tamron SP AF 90mm f/2.8 Di macro - the new lens is weather-sealer and it keeps a constant physical length throughout its focus range.
The broader rubberized focus ring operates smoothly and without play. Just like most macro lenses, it has a focus limiter so you can select the focus range to reduce AF hunting e.g. in non-macro scenes. A barrel-shaped lens hood is also part of the package.

The Tamron lens features a virtually silent USD (Ultrasonice Drive) similar to Canon USM (Ultrasonic Motor). AF operations are very fast at conventional distances. This is at least partially achieved by implementing a rather short focus path which makes life a little harder in manual focusing mode. Full-time manual focusing (FTM) is supported. The AF accuracy of the tested sample was good in phase-detection AF mode. It didn't overly like LiveView (contrast AF) though.

Another new feature is the optical image stabilizer - or "VC" = Vibration Compensation according to Tamron naming conventions - with a claimed efficiency of up to 4 f-stops. However, take this as an optimistic statement as usual.

Here's a spec comparison between the Tamron and, its direct competitors, the Canon EF 100mm f/2.8 USM L IS macro and Sigma AF 105mm f/2.8 DG HSM OS macro: