Review by Klaus Schroiff, published December 2010

Introduction

The build quality of the lens is nothing short of outstanding - that's probably the very first time for me to praise a ~300mm zoom lens like this. The lens body is made of metal and everything is tightly assembled and also sealed against dust and humidity. The inner lens tube (also made of metal) extends when zooming towards the long end but there's not even the slightest hint of wobbling here. The focus ring operates silky and the zoom ring feels very smooth as well. There's a transport lock (70mm setting) in order to prevent zoom creeping but our sample showed no tendency to do so anyway. The front element does not rotate during focus operations so using a polarizer remains easily possible. The lens does not feature a dedicated tripod mount straight from the factory but it is an optional accessory.

The ring-type USM AF is blazingly fast and near silent. FTM, full-time manual focusing, is possible in one-shot AF mode. LiveView-(contrast)-AF is reasonably fast. The AF accuracy of our test sample was very high. Just like most Canon tele lenses it features an image stabilizer (IS) which is supposed to give you an extra potential of up to 4 f-stops. You should take this with a little grain of salt but it seems to come quite close actually. Unlike the consumer variants the IS system has 2 modes - a normal one for static shooting (horizontal + vertical stabilization) and a panning mode (horizontal OR vertical stabilization - the panning direction is automatically detected). The IS also supports tripod detection so it can remain activated here.

Here's a comparison with its nearest cousins: