This is a really lovely lens to use. It has perfect balance when mounted on a Canon EOS 5D Mk II, its removable tripod-mounting collar falling neatly into the user’s left palm. The rubber-grip zoom ring is perfectly placed and offers just the right amount of resistance. A slight shift of grip is needed in order to reach the manual-focusing ring but this will doubtless be needed less often than the zoom ring, immediately justifying Canon’s design priorities.

There are four two-position slider switches located between the two rings, mostly within thumb’s touch although the lowermost is a little awkward to reach. The top slider sets the focusing range, allowing either full movement or a curtailed minimum object distance of 2.5m; the next slider switches between AF (with full manual intervention) and pure MF; the third activates the Image Stabilizer (sic); and the last, and most tucked-away, selects the prevailing IS mode.

Canon’s two image-stabilisation modes are designed to combat multi-directional vibrations caused by camera shake when photographing subjects that are essentially static (Mode 1), and specifically
perpendicular camera shake when panning the camera either horizontally or vertically (Mode 2). In both cases, automatic focusing is brisk and quiet.

The only real fly in the ergonomic ointment is the lens hood, which is a reversible type but cannot be left stowed as it totally blocks the MF ring and four two-position switches, as well as impeding slightly on the default grip position. If I owned this lens I would keep the lens hood detached and loose at the bottom of the substantial padded case that accompanies the zoom.

Technical testing revealed some excellent results but also a little over-ambition on Canon’s part. Peak resolution hits 0.40 cycles-per-pixel at f/4, which is absolutely amazing, but drops right down to 0.17 cycles-per-pixel at f/32. Except in dire emergencies it would be better to use apertures no smaller than f/22 and further restriction to f/16 would ensure that the resolution hardly dropped below 0.3 cycles-per-pixel. In theory the zoom’s small-aperture performance could have dropped its Image Quality rating by two points but the likely rare use of these settings in a lens such as this has resulted in only a one-point penalty.