Canon EF-S 17-85mm f/4-5.6 IS USM was release in mid-August of 2004 and on APS-C type cameras, for which it was specifically designed, has a field of view equivalent to that of a 27-136mm lens on a full-frame camera. Priced at about US$500 (as of February 2007), the lens falls within Canon's consumer-oriented line and is often considered as an upgrade from Canon's standard EF-S 18-55mm f/3.5-5.6 USM kit lens. The build quality is average at best - dual cams are wobbling and squicking, plastic barrel feels cheap and the zoom ring is jagged. Both AF/MF and IS switches are a bit flimsy, although I don't think you are in danger of accidentally switching either one when hand-holding the lens. On a positive size, both zoom and focus rings are rubberized and provide a good grip. As mentioned earlier, this is an EF-S lens designed for APS-C type cameras, rendering it incompatible with full-frame and APS-H cameras.
The lens construction consists of 17 elements in 12 groups, sporting 3 aspherical glass elements. Canon EF-S 17-85mm f/4-5.6 IS USM offers full time manual and a ring-type USM auto-focus. The minimal focusing distance is 35cm (1.15ft) and the maximum magnification of 1.5x at 85mm. The lens is quite compact and lightweight at 78.5x92mm (3.1"x3.6") and 475g (16.8oz). Featuring a conventional zoom mechanism rather then an IF, the lens cams extend during zooming, adding a few centimeters to the overall length of the lens. Thankfully, the front element of the lens does not rotate, making it possible to attach circular polarizer to the front filter mounting thread of the lens. Filter size is 67mm. Canon EF-S 17-85mm f/4-5.6 IS USM includes a second generation Image Stabilizer which could help you gain up to three f-stops when hand-holding the camera. The auto-focus is quite fast and silent.
The factory box includes Canon EF-S 17-85mm f/4-5.6 IS USM lens, front and rear lens caps, manual and a warranty card. The lens accepts EW-73B lens hood (sold separately). You can also use LP1116 soft case, also sold separately. The lens is compatible with Canon's extension tubes EF 12 II and EF 25 II. You can also attach gelatin filters to the lens using Gelatin Filter Holder IV at the expense of the lens hood which cannot be used with the holder.
|Lens Composition||17 elements in 12 groups|
|Angular Field||78-18 degrees|
|Focusing Action||AF/MF, USM
|f-stop Scale||f/4-f/22, camera-controlled|
|Lens Hood||EW-73B (optional)
|Lens Case||LP1116 (optional)|
Canon EF-S 17-85mm f/4-5.6 IS USM showed average overall results. The lens is very sharp in the center, but the border quality is unimpressive across pretty much entire zoom range. The lens shows some noticeable barrel distortion when wide open. Vignetting is also on a high end, which could be explained by the fact that this is an APS-C type lens with a reduced imaging circle. Stopping down to f/5.6 or f/8 helps reduce vignetting. The lens also showed pronounced chromatic aberration, primarily around 17mm to 35mm. While disappointing, it's not the end of the world since chromatic aberration can be corrected with a variety of post-processing tools.
IS is a great addition in this lens and helps you gain extra 2-3 f-stops when hand-holding the camera - a much needed feature for this relatively slow lens. Many would argue that the main benefit of this lens is its versatility since the lens covers a pretty aggressive zoom range. That would have been the case if the lens did not stink in the wide zoom range.
Canon EF-S 17-85mm f/4-5.6 IS USM produced very mixed results. The lens is really sharp in the center, but the border quality is dismal, especially at the wide angle. Things get better in the middle range - the lens is sharpest around 35-50mm, but the quality degrades again towards telephoto zoom. At its best, the lens would produce good 11in prints (35mm FL). You will still be able to get ok 16in prints as long as you avoid the wide side of the zoom range. Conclusion? 17mm-24mm range is simply mediocre, so I found myself avoiding that range in favor of telephoto side. Should you bother with this lens or just find one with a more conservative zoom? That will depend on your needs.
Chromatic aberration was quite pronounced around borders at the wide side of the zoom range (17mm through 35mm), where it exceeded 2 pixels and persistent throughout all aperture settings From 35mm and on, CA was very minimal at borders and nonexistent in the center.
The market is literally flooded with standard and medium telephoto zooms. Naturally, Canon EF-S 17-85mm f/4-5.6 IS USM, which aims to be a standard 'walk-around' lens, has quite a few competitors. Within the Canon camp you might want to consider its sister EF-S lens the 17-55mm f/2.8 IS USM (review), which is a few hundred dollars more expensive, but also performs significantly better. You might also want to consider Canon EF 28-105 f/3.5-4.5 II USM (review) which is priced about the same level. Also take a look at Sigma 17-70mm f/2.8-4.5 DC MACRO (review) and Tokina AT-X 535 PRO DX AF 50-135mm f/2.8 (review), both of which are priced competitively and exhibit better performance then Canon EF-S 17-85mm f/4-5.6 IS USM. As I have been saying in my other reviews, there is no such thing as free lunch, so prepare to either shed a few bucks more or trade some lens characteristic (Image Stabilizer for example).
The build quality of this lens is one of the major drawbacks. Border quality at the wide zoom range is another one. All-in-all, the lens tries to be a lot of things but fails in most of them. Considering that the lens produces mediocre results on the wide side of the focal length, why not to go with a more conservative zoom? The lens is still better then the standard Canon kit lens but not by much. IS is always welcome and could help save the day in some situations but is rarely an answer to all issues. Furthermore, pricing of this lens leaves some questions - for extra hundred dollars you will be able to buy Canon EF 17-40mm f/4L USM lens, a superior lens in every aspect. Considering that there are quite a few alternatives available on the market, I would suggest taking a look at them before making a final decision.