Superzoom lenses like this one are so convenient. You don’t need to carry around extra lenses and you don’t have to keep swapping lenses as you work (and risk getting dust inside the camera). A single superzoom lens is potentially capable of just about any photographic project you might want to undertake, from travel shots to sports, portraiture and even close-ups.

But lenses like this are heavier and more expensive, and these are just the obvious issues. There are optical compromises too, which mean that superzooms can lose definition at their maximum focal lengths and they can be more prone to distortion and chromatic aberration.

This lens uses Canon’s EF-S fitting. That means it’s designed solely for EOS models with smaller, APS-C sized sensors. This includes the EOS 1000D, 400D, 450D, 40D and new 50D. You can’t use it on the EOS 1D or 1Ds, which have larger sensors and lens mounts. The 18-200mm focal range equates to 29-320mm, so it matches the standard Canon kit lenses at the wide-angle end of the range, but also goes right up to a medium-long telephoto setting at the other end of the scale.

It is a pretty big and substantial lens, but not that long at minimum focal length and it does balance quite well even on a smaller EOS SLR like the 400D. It’s quite ‘fat’ too, but the shape is neatly cylindrical, and the camera and lens combination should fit easily enough in a standard holster or camera bag.

The lens does extend considerably at longer focal lengths, but there’s little or no wobble in the two extending barrels, and the whole thing feels solid and well made. The zoom action is quite light and even, except right at the very end of the zoom range. There is a locking switch to prevent zoom creep – some superzooms gradually extend if the camera’s carried pointing downwards – but it’s not a problem here and the lock isn’t really needed.

Focusing is fast and quiet, as we’ve come to expect from Canon lenses, though it doesn’t quite match a shorter range zoom for speed. The manual focus ring is quite light, but smooth and accurate enough for the job. The front lens element doesn’t rotate during focusing, so this lens is ideal for photographers who use filters.

On the side of the barrel are flush-mounted switches for Auto/Manual focus and switching the Image Stabilisation system on and off. These are firm and positive – they’re easy to move, but you’re not going to do it by accident.

Canon (along with Nikon) favours lens-based image stabilisation systems. It makes the lenses more expensive, but the advantage is that the image is steadied in the viewfinder as you shoot. And it’s a big advantage with a long lens like this one, because at maximum focal length it’s quite tricky to keep objects centred in the viewfinder without it.

Our lens tests produce a pretty typical set of resolution figures for a superzoom lens. The Canon is sharpest at short to medium focal lengths and at full zoom it does lose some definition. It’s quite sharp in the centre of the frame even wide open, but the edges are some way behind and you need to stop down a little before these sharpen up to match the centre (this is what’s dragged down the full aperture figures somewhat in our test results).

What the resolution figures don’t show is that there is a fair amount of red/cyan colour fringing at the edges of the frame at 18mm. This does diminish at longer focal lengths, but never quite goes away. On the other hand, while there is some fairly pronounced barrel distortion at the wide-angle end of the range, there appears to be little or no pincushion distortion at medium to long focal lengths, and this is pretty rare in a lens of this type.

Test shots taken with this lens confirm the results of the lens tests. This is a good, sharp lens at short to medium focal lengths, but at full stretch the results do look a little soft. It’s okay for occasional use, but if much of your photography is at long range, you might be better off with a dedicated long telephoto.

The other possible issue that may put you off this lens is the price. The EF-S 18-200mm is good, but not exceptional, and £550 seems a lot to pay for something that’s not going to blow you away. However, a quick scout around reveals that when it’s bought with a new EOS SLR as a kit, the real price is closer to £300 – a much more acceptable investment.

Overall, this is a very interesting option as an alternative ‘kit’ lens, then, but less attractive as a standalone purchase.

Final Verdict This is a good buy for Canon fans looking for convenience and versatility, but third-party superzooms are cheaper. Full-time long-range photographers will be better off opting for a dedicated long telephoto OVERALL

Our lens reviewer, and technical expert, Rod is a veritable photographic encyclopaedia. His illustrious CV has seen him write for many mags, websites and journals.