It’s not easy deciding on the best lenses to get for your EOS SLR, and Canon’s just made it that much harder. This brand new 15-85mm is a high-spec, high-quality ‘standard’ zoom for EF-S format Canons – they’re the ones which aren’t full-frame, and include the EOS 1000D, 450D, 500D, 50D and the new 7D. Its equivalent focal range is 24-135mm, which covers a classic focal range from 24mm (extra-wideangle) to 135mm (medium telephoto). This gives the new lens a useful advantage over Canon’s standard 18-55mm kit lens at both the wideangle and the telephoto ends of the zoom range.

So is it now the best standard zoom of all for Canon’s EF-S format SLRs? Well, sort of, and maybe. There are two things that users might be looking for in a top-quality standard zoom (we’ll take image quality for granted), and these are zoom range and a constant maximum aperture.

This new 15-85mm certainly goes wider than any of Canon’s other standard zooms, but not longer. This honour goes to the 18-135mm zoom launched at the same time, and which we tested last month. And if you want a constant maximum aperture lens, you should go for the 17-55mm f2.8 instead. Tricky, isn’t it?

This lens would be a good choice, though, if you’re looking for an all-rounder with an extra bias towards wideangle photography. In fact, it’s the spiritual successor to Canon’s long-serving 17-85mm IS lens, often chosen as a ‘quality’ kit lens in the past for Canon’s professional and semi-pro EF-S cameras, like the EOS 20D, 30D, 40D and 50D.

It’s not clear yet whether the 15-85mm will replace the 17-85mm, but the price of the 17-85mm does seem to have been falling, and it’s now up to £240 cheaper than the new 15-85mm. Now that’s a big price difference for an extra 2mm focal length at the wideangle end. Currently, the 15-85mm is selling for around £640 online, which is a fair wodge of cash, though dealer discounting may bring this down before too long.

So what exactly are you getting for your money? Apart from the slight increase in focal range over the 17-85mm, you get a modest increase in maximum aperture at the wideangle end from f4 to f3.5. Canon says the image stabilisation system in the 15-85mm offers a four-stop shutter speed advantage and this lens boasts Canon’s new, improved exterior design, although to be perfectly honest it’s hard to see what was wrong with the old one.

Optically, this lens is very good. It’s more consistent than most zooms across its focal range, with excellent sharpness at 15mm and 40mm and good sharpness still at 85mm. It’s good across the aperture range, too, so you don’t need to stop down to get the best quality. It seems a bit less prone to chromatic aberration than the old 17-85mm, too, and while there is some barrel distortion at 15mm, it’s fairly well controlled, swapping to mild pincushion distortion at the middle and long end of the zoom range. You can’t expect optical perfection in any lens, whatever the price, but you can expect to get better overall performance as the price goes up, and that’s just what the 15-85mm delivers.

The handling is good too. The zoom control is smooth, albeit with a slight tight spot in the middle of the range. Canon’s USM autofocus is as fast and quiet as ever, and includes full-time manual override, so you can fine tune the focus manually before you shoot. The focus ring is quite narrow, though, and while this lens does have a distance scale it’s quite near the camera body and depending on the angle you’re looking from and the body you’re using, it could be partially obscured by the pentaprism overhang.

The image stabilisation works well, and you really notice the benefit at longer focal lengths, where it visibly steadies up the image in the viewfinder as you half-press the shutter release. There’s an IS switch on the side of the lens but you’re unlikely to need it because Canon says this version has automatic panning and tripod detection. This means that the lens won’t try to ‘stabilise’ horizontal movements when you’re taking panning shots, for example.

So is this lens worth the money? Probably, but only if you’re an enthusiast or pro using one of Canon’s high-end EF-S cameras like the EOS 50D or EOS 7D. Bear in mind that the new 18-135mm lens is cheaper and offers a longer focal range, while Canon’s 17-55mm f2.8 lens offers a constant maximum aperture. It’s not really a case of which one is the best, but which one most suits your particular needs.

Final Verdict The EF-S 15-85mm’s unusually wide zoom range and high optical quality make it a good match for high-end cameras like the EOS 50D and 7D. 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.