Review by Klaus Schroiff, published April 2009

Special thanks to Markus Stamm for providing this lens!

Introduction

The design of a 10.7x zoom is complex so it doesn't come as a surprise that the EF 28-300mm L IS is a rather large massive being. Typical for most recent L class lenses it is build to professional standards including a sealing against dust and humidity. The latter is certainly a smart move because dust is a frequent problem with other "air sucking" zoom lenses. The lens has a push/pull zoom mechanism - this approach allows a fast change of the focal length but the fine-tuning of a setting is a little more difficult here. For press photography where things tend to be hectic at times this may be appealing whereas most other users would have probably preferred a conventional zoom ring. Fortunately the zoom operation is very smooth and you can get really used to it after a short while. Just like most long zoom lenses the EF 28-300mm L extends significantly towards the 300mm setting and the petal-shaped lens hood adds some extra centimeters - an impressive sight. A push/pull zoom is doomed to suffer from lens creeping so Canon added a control ring to lock the lens at a desired position. The lens is _not_ compatible to the two Canon EF tele-converters.

As already mentioned above the 28-300mm L IS features a 3rd generation image stabilizer. Canon claims a gain of three f-stops here which seems to be pretty accurate. Unlike older IS lenses the stabilizer also detects the lack of movement so it can remain activated for tripod usage. Typical for Canon pro grade IS lenses the IS offers two operation modes:

• standard (mode 1): corrects movements for static scenes (horizontal plus vertical stabilization)
• panning (mode 2): corrects the vertical axis only (regardless of the lens' orientation).

The AF drive is a ring-type USM (ultrasonic) variant and combined with a rear-focusing group it provides very fast and near silent AF operations. The AF accuracy was good during the field tests with our sample. Full-time manual focusing is possible in one-shot AF mode. Due to the very broad focus range Canon also implemented a focus limiter so you can exclude close focus distances in difficult situations where the AF may tend to hunt throughout the focus range. However, usually this isn't really needed.