I acquired the Canon EF-S 17-85mm F4-5.6 IS lens when I purchased a Canon 350D in March 2005. I chose this particular lens to go with that camera for several reasons: the zoom range is comparable to 27-136mm on full-frame cameras (thus providing crop sensor body coverage similar to a film SLR 28-135mm zoom); it is small and light; the optical quality was described as being pretty good; the build quality seemed reasonably good; IS (image stabilization) somewhat compensates for the relatively small minimum aperture, especially at the longer focal lengths where stability is a greater issue. (The EF-S designation indicates that this lens is only for 1.6 crop factor cameras like the 350D and the 20D and their successors.)

The size and weight of camera equipment can be significant considerations for me since I often carry the equipment on the trail for a day or as long as two weeks. In many situations the 17-85mm lens could cover the core of the focal lengths I really need. This means that in certain situations this one lens might be sufficient, lightening my load and simplifying my lens choice – the lens is always on the camera.

When I used this lens I normally left it attached to the camera, which rode in a Tamrac Zoom case around my neck/shoulder and was easily accessible, even while wearing a backpack. This let me act quickly to get shots that might otherwise not be there if I had to remove my pack, switch lenses, and so on.

What about the optical quality of the lens? I’d rate it as decently good if you operate within its limitations.

• On a tripod at apertures around f8 it can be decently sharp in some cases, though I do not feel that it can produce consistently very sharp results at print sizes much beyond letter size. Sharpness is fine for typical web phots.
• There is some noticeable softness in the corners, especially at wide angle settings, and there is no way to fix this in post-processing.
• There is quite noticeable vignetting at the larger apertures. (And the larger apertures aren’t all that large on this lens…) The vignetting can be corrected in Photoshop*.
• Barrel distortion is not insignificant on this lens, especially at the wide end where the effect is quite noticeable on vertical or horizontal lines near the edges of the frame. This is also fixable with Photoshop.

(I note that many buyers in the target market for a lens like this one probably do not have Photoshop …)

The image stabilization works well. Build quality isn’t bad, though this lens does not operate quite as smoothly as my “L” lenses – but that is to be expected.

Overall, as an “only lens” the 17-85 EF-S can perform decently. The convenience of this lens may compensate for the image issues in many situations. As a one-lens backpacking setup, I liked the combination of this lens and the “Rebel” XT/350D for ease of use. It also works for unobtrusive urban photography. However, if really good optical quality is paramount and/or you intend to make larger than letter size prints, you may not be fully satisfied with this lens.

Update 2/8/08: I no longer use this lens. (I shoot full frame now.) I have updated the above description to better reflect my eventual experience with it and a current evaluation of the strengths and weaknesses of this lens follows.

Strengths: At a reasonable price this lens provides a good set of features for many crop sensor camera users. The focal length range nicely covers the central range for most entry-level photographers in one lens. The image stabilization (IS) feature can be useful in low light hand held photography. The lens is relatively small and light for what it does. For most users the image quality will be quite fine for online jpg sharing and for prints up to letter size. Build quality is OK.

Weaknesses: The variable maximum aperture of f/4 at the wide end (17mm) and f/5.6 at the long end (85mm) limits the usefulness of the lens for photographing moving subjects in low light. Note that the onset of diffraction blur beyond about f/8 on a crop sensor body means that you may only have two useful apertures at the long end – and one of those is “wide open!” While image quality may be sufficient for some types of use, there are issues: excessive corner light fall-off and noticeable corner softness, especially at extremes of aperture and focal length; more than average pincushion/barrel distortion. Build quality is OK but there can be some issues such as lack of smooth zooming. Image quality does not consistently hold up in prints larger than letter size.

Bottom line:

This can be a decent lens if you are moving to a DSLR to the first time from a point and shoot camera, and with care it can serve beyond that level to a certain extent. On the other hand, you might be just as happy with the newer image stabilized version of Canon’s EFS 18-55mm kit lens.

If you are looking for a single lens solution, don’t generally make large prints, mostly shoot subjects where some pincushion/barrel distortion isn’t a problem (e.g. family, vacations, outdoor), really need to emulate the functionality of a SLR 28-135mm lens on a crop sensor body (e.g. Digital Rebel or Canon X0D series body), or just need a more versatile “kit lens,” this lens can serve well. If you are concerned about the corner issues, if your photography includes a lot of subjects with lines parallel to the edges of the frame, or if you will make larger prints this lens may not meet your requirements.

If my write-up helped you with your decision, you can purchase this product from B&H Photo via this link and help support this web site – thanks!