Canon EF-S IS USM 17-85mm f/4.0-5.6 Lens

This lens is big for the zoom range & max aperture - but then it does have to accommodate the US AF motor and the Image Stabilization mechanism.

It basically does what it says on the box. Auto focussing is fast and accurate, and with my 50D, you know exactly what it has focussed on. The IS works like a charm - hand-holding 1/15s without any special effort gives essentially perfect results.

The lens is adequately sharp right into the corners. If there's vignetting, I haven't noticed it :)

Manual focussing is easy, despite the restricted degree of rotation (about 100 deg) of the focussing ring. The zoom ring is large & easy to use with a very smooth movement.

The front of the lens does not rotate when zooming or focussing so you can use rotation sensitive filters without problems.

By itself it's pricey but if you buy it as part of a kit with a camera, it's a bit more reasonable (I think you generally save at least £100 in the UK).

On the negative side, using the IS to enable you to work in lower light levels without flash is good - but it really is *not* the same as having a large maximum aperture. The issue is depth-of-field. When shooting at night, I often want to use the lens wide open to isolate the subject against a blurred background and that's not so easy with this lens so a bit of post-processing is sometimes called for.

Of course, what I really want is something like 11 - 85mm f2.8L IS USM but (a) they don't make it and (b) I guess it'd be around £2000 :{

In the meantime, I'm happy with this lens.

This is a perfect wide angle to short telephoto lens for the amateur who has just learned how to use his/her digital SLR. It is of significantly higher quality both in build and performance, compared with the ubiquitous 18 to 55mm lens that comes so frequently packaged with lower end digital Eos cameras. The main reason I gave it only 4 stars is because the maximum aperture is that little bit smaller than I would have liked at f4-5.6, but, hey, you're getting a high quality general purpose lens for a fraction of the cost of a heavy, ultra fast piece of high end Canon kit. One would have to pay 3 times the price for a near equivalent zoom with a maximum aperture of f2.8. Don't pay TOO much attention to the detailed testing that has been done for this lens. There is no doubt that test chart peformance is poor compared with, for example, Canon L lenses, which are, of course, much heavier and more expensive. In the real world, the lens actually performs very well, and certainly better than one would expect from the hard test chart information. If you spend much of your time photographing test charts, this is NOT the lens for you. You will need to invest in heavy L glass to keep you happy!
SUMMARY
This is an excellent lens for the serious amateur who wants a quality general purpose zoom without paying for, and having to lug around, its heavy glass stablemate. If you don't need to shoot in ultra low light without a flash, and you're happy to forgo a maximum f stop of 2.8, this is undoubtedly the lens for you. It is rugged, solid without being too heavy, and will provide excellent service for many years to come, wherever your hobby takes you.

I SHOULD LIKE TO ADD ONE CAVEAT FOR THE BENEFIT OF THE EMBRYONIC AMATEUR. THIS LENS, HAVING THE "S" SUFFIX WILL NOT FIT MANY HIGH END EOS CAMERAS, SUCH AS THE 1D MARQUES 1 TO 3. CHECK CAREFULLY FOR COMPATIBILITY BEFORE PURCHASE.

This lens is a great addition to any Canon digital SLR outfit. It covers the focal lengths required for interior through standard to portrait and short telephoto. Being a USM lens it focuses almost instantly and silently and having the image stabiliser means that seriously slow speeds can be hand held without danger of camera shake. It is easy to operate and reasonably light weight. A far better lens than the 18-55 lenses often provided with Canon DSLR kits.

On the negative side, it is chunkier than the standard bit of kit and it doesn't fit in the hard case designed for the camera but who cares really. The hard case is one of the most badly designed bits of toot Canon have ever come up with anyway.

I thoroughly recommend this lens to anyone using a Canon DSLR.

This is one of the optional kit lenses for the 20D/30D & 40D cameras.
As a non 'L' lens it is very good, and is excellent value (especially if bought as part of a kit with a body).
Until the end of June 2008, Canon have a £40 rebate on this lens (you must provide the bar-code, and receipt) so double check with your retailer.

Compared to the 18-55mm that many of the range come with, this is massive, but it's a reasonable size and weight for what it does.
The optical image stabilisation works well, and it covers a good range of focal lengths (27mm to 136mm equivalent field of view).
The front element doesn't rotate during focussing or zooming, and the recommended hood (the EW-73B) is a petal type that can be stored back to front on the lens.

Summary: While optically not quite as good as the 17-40mm F4L or 24-105mm F4 L lenses, it is a fraction of the price (and weight) of either.

I bought the Canon 17-85mm after reading numerous reviews about it. Many reviews complain about how bad the distortion is, how bad the chromatic aberrations are, etc. I've found those issues only when shooting test charts. If you shoot test charts, this is not the lens for you.

In practice, I've found this lens to be superb. The 17-85mm range is very useful when walking about. I'm personally a wide angle shooter, preferring extra wide angle lenses and I feel that the new (and more expensive) Canon 15-85mm would serve me better. Having said that, 17mm is fairly usable and if I stop down to f/6.3 or smaller I get very sharp results across the frame.

Focusing is a little difficult under low light. In situations where my Canon 50mm f1.8 works flawlessly this lens has a tendency to hunt. That's likely due to the max aperture of f/5.6 which is a little too slow for low ambient lighting shots. If you slap on a flash gun, the AF assist beam fires and focusing becomes a non-issue. You'll lock focus each and every time. Most of the time though, you'll find the focusing adequately fast and fairly silent.

The IS is fantastic. It works and I'm able to handhold shots at 1/8 seconds which I'm thoroughly pleased about. That doesn't help when shooting moving subjects, but it's great for shooting indoor architecture (think churches and museums). This was something that I felt was lacking in my current lens lineup.

Pros: Relatively cheap, light, good image quality.
Cons: Slow max aperture, build quality could be better.

Can I recommend this lens? Yes!