My 17-85 IS has turned out to be a bit of a Jeckyl and Hyde lens. At the wide end it’s allergic to straight lines, soft unless stopped down – and hardly perfect when it is - and paints wide purple fringing around anything slightly contrasty. Set wide I find myself having to work hard both while taking the shot and in post processing to get anything more useful than a 6x4 holiday snap. Zoom out to 28mm and there’s a marked improvement, at 35mm it’s transformed – while from 50mm to 85mm it’s very sharp.
Image Stabilization technology does what it says on the tin – allowing you to operate in aperture priority mode, stopping down for clarity and making up for it by eliminating camera shake in some mysterious Hogwarts-like fashion.
IS doesn’t make up for a very slow shutter speed though if you need to take pictures of fast-moving objects or people. In this respect the 17-85mm is let down because it’s really an f5.6 lens masquerading as an f4 for a few measly focal lengths. Still, hand-held shots at 85mm with a shutter speed of 1/15 (1/8 if you can stabilise yourself in a makeshift fashion against a wall or table) showing a clear, shake free image at 100% blowups, can’t be bad.
It seems to have a lot of negative reviews because it’s not as good as an L lens. This is Canon’s own fault if this lens’ retail price is close to the 17-40L, and clearly a lot more than ‘the poor man’s L’; the Tamron 28-75mm f2.8. But it’s still a long way off the price of a 24-70mm f2.8, for instance. Either way, a current average of 7.6 here on FM does this lens a disservice and if you have a 350D/20D, you should give it a good try if possible before you consider anything else, cheaper or more expensive. I recently field tested it against a range of lenses, either borrowed or bought on SOR, including a Sigma 18-50mm F2.8, a Tamron 24-135mm f3.5-5.6 SP, a Tamron 28-75mm f2.8, a Canon 50mm f1.8II AND a Canon 24-105mm F4L IS. Here are my observations.
VS Sigma 18-50mm f2.8: No contest from 18-28mm – the Sigma has much less barrel distortion and no CA to speak of. Then suddenly the Canon comes back into the game – from 35mm to 50mm it is equally sharp, better at f8. And the Sigma’s hearty red bias isn’t to my taste. Plus there’s an extra super sharp 35mm to play with on the Canon.
VS Tamron 24-135mm SP: This is a great lens and to be honest there’s little to distinguish between it and the Canon from 35-85mm (it’s better than the Canon below that, and overall has a slight edge on contrast) – but only stopped down to f8 or f11 and on a tripod. The Canon is sweeter wide open and IS also comes into play. Hand held at 85mm there is no contest, the Canon wins unless you’re shooting above 1/250 and the Tamron is a pretty slow lens. I found I could get steadier, clearer, sharper crops from the centre of the 85mm Canon image than I was getting from the Tamron zoomed to 135mm. The Canon also focuses much faster. IS is worth the extra money if you're not a regular tripod user.
VS Tamron 28-75mm f2.8: Now this is a formidable lens, yet from 35-75 at f5.6 the Canon matched it for sharpness scene for scene. Likewise at f8, f11. Maybe I had one of those infamous ‘bad batch’ Tamron lenses, but I actually thought it was excellent – strikingly clear. F2.8 was lovely and this lens has such a bright viewfinder image and beautiful bokeh; yet I had more consistent, ‘shake free’ hand-held images from the Canon in all lighting situations and for a standard zoom this is the most important thing.
A small gripe though: For a lens this much more expensive than either of the Tamrons, it’s a shame Canon can’t include some thoughtful features that both have: like a zoom lock or a bundled lens hood, or indeed lens cap that can be easily removed when a hood is mounted. Grrrr….
VS Canon 50mm f1.8. Comparible results at all apertures above f5.6. Better results hand-held for the 17-85mm and to my mind slightly better contrast. Obviously f1.8 is great, but IS compensates well for static shots.
VS Canon 24-105mm L IS. This lens was the holy grail. Having identified that my hands were probably too shaky for a non-IS lens, I thought the latest L would be the ultimate combination of quality, IS and zoom coverage (with a hood included in the price!). Brighter through the viewfinder itself, the images looked identical on the computer screen initially, but dammit if the L wasn’t slightly softer wide open from 24mm right through to 85mm on a 100% crop. This is a bit deceptive I guess because the 17-85mm switches to f5.6 around 45mm, while the L stays at F4. Stopped to f5.6 all the way, the L came back on board, while prints showed slightly more pleasing contrast. But is it worth the price? Common sense says not.
Conclusion: Apart from pricing it too close to the bargain basement L Canon also seems to have shackled the 17-85mm with such poor wide end performance that people are instantly turned off, as I think I was initially when I got it as part of my 20D kit (having had the Tamron 24-135 on my 300D). I haven’t the time or skill to conduct proper lab tests, but these rough static outdoor head to head tests reveal a quality lens – yet all of these competing products are rated far higher here at FM.
The wide end isn’t an issue any more as I’ve got a 10-22mm EF-S, another quality lens – one rated much higher than the 17-85mm, but similar in so many ways and not just the crop factor mount. My guess is if Canon had limited this lens to a 28-85mm zoom range rather than trying to achieve the barrel distorting, CA-inducing, ultra wide end too, it would have achieved similar ‘almost L’ accolades.