Review by Klaus Schroiff, published August 2011

Special thanks to Alexandre Grandrémy for providing this lens for testing purposes!

Introduction

The Sigma lens belongs to the EX ("Excellence") lineup thus the professional lens segment. The build quality is superb with a body made of rubber-coated metal based on a metal mount. The former crinkle-style EX finish is no longer used. The broad, rubberized focus ring operates smoothly - something that macro photographers will surely appreciate. The physical length of the lens remains constant throughout the focus range and the front element does not rotate, of course. The two-segment lens hood is a bit of a specialty by Sigma - the segments can be stacked in order of providing an even better protection when used on an APS-C DSLR. Such an approach may make sense on paper but it doesn't feel overly useful to us because the base segment is already deep enough. Anyway, it's not a drawback but a feature in any case and this is a full format review. The supplied tripod mount is removable.

The AF is based on Sigma's ultrasonic motor (HSM) which operates both very fast (except in low light) and virtually silent. The tested sample focused accurately in phase-detection (standard) AF mode. The speed in contrast AF (LiveView) is about average in the true sense. Full-time manual focusing is supported. Accurate manual focusing a bit tricky though because the focus path is relatively short for a macro lens (about 160 degrees).

As already mentioned there's one differentiator over the old model - OS (Optical Image Stabilization). Sigma claims an efficiency of up to 4 f-stops. This seems about right for non-macro scenes. However, it seemed more like a 2 f-stops improvement for macro work.

It is also worth to mention that the lens is compatible to Sigma's APO EX converters resulting in either a 210mm f/4 (1.4x) or 300mm f/5.6 (2x) combination. The OS remains functional in this cases and the max. object magnification in macro setup increases to 1.4:1 and 2:1 respectively. Alexandre was so kind to lend us his Canon EF III converters which can be used as well. Surprisingly the phase detection AF is only functional with the EF 1.4x III (on the EOS 5D II) - LiveView (Contrast AF) is also supported with the EF 2x III. We'll provide some performance numbers for those as well on the following pages.