Canon EOS 7D - EF-S15-85mm f/3.5-5.6 IS USM - ISO 1600 - 1/6 sec at f / 4.0 - handheld
Gallery: Granville Island Night
When I tell people what a great lens Canon's EF-S 15-85mm "kit" zoom is (introduced along with the EOS-7D in 2009), I often times get some pretty skeptical looks. After all, while Canon makes many superb 'L' lenses, they don't necessarily have a reputation for high quality kit lenses. Well people... take my word for it, the 15-85mm zoom rocks! The above gallery contains all images taken with this lens the other evening, all handheld and most are wide-open at f/3.5. I did some perspective correction on several shots in Adobe Lightroom v3.3RC to square up the buildings when I wasn't quite shooting level and please note that LR v3 now does do some automatic distortion corrections for many lenses too, although even without correction it really is not bad. I have included 2000 pixel images as well so you can better see how sharp this lens can be. Images were shot raw with my EOS-7D, all at ISO 1600 and at shutter speeds ranging from a very long 0.4 seconds, to an 1/8 of a second with a handful being slightly higher. EXIF data shows below each enlarged image, so you can see the camera settings.
Between 15mm and 70mm, I would stack this zoom up against any 'L' zoom from an image quality standpoint although once you approach 85mm, it can get a little soft wide open and starts to give more of a "kit zoom" look. However below 70mm and especially at the wide end, it even manages to equal some primes at any given f-stop. For example, compared to my EF 24mm f/1.4L II, it more or less matches it for sharpness, even in extreme corners, at f/4 and above. Of course, on the EF-S 15-85mm, wide-open at 24mm is f/4 and my 24mm 'L' prime opens up all the way to f/1.4. In any case, I think you get the idea... it is generally an excellent lens!
Another kit zoom, the really inexpensive (and all-plastic) EF-S 18-55mm IS, is also quite sharp although it suffers from some slightly hard-to-describe issues. Although crisp, images sometimes seem too contrasty or have a "nervous" look about them, almost as though the lens was really working overtime to give you a sharp result. This is visible in both out-of-focus (bokeh) areas and along high-contrast edges at times. In contrast, a good 'L' lens, or the EF-S 15-85mm zoom, seem to have a more relaxed way of serving up images, rendering them sharply but seemingly doing so without having to break into a sweat. Hmm... not a very technical analysis, that's for sure, but maybe it explains what I see? It still doesn't match the truly "effortless" image quality of the best 'L' primes I've used, such as the 17mm TS-E or the 35mm f/1.4L for example, but the EF-S 15-85mm sure is in a whole different league compared to most other kit zooms.
Comparing it to the Canon EF 24-105mm f/4L IS on a full-frame body like a 5D Mark II, I would most definitely give the EF-S 15-85mm on the 7D a distinct edge from a lens image quality standpoint, regarding edge and corner sharpness as well as distortion. Also, I have not seen as much IS-induced corner softness on the 15-85mm zoom as on some other stabilized wide-angle zooms I've used. For example, in my experience the otherwise excellent EF-S 17-55mm f/2.8 IS can suffer badly from random corner blurriness if you happen to snap a photo while the IS system is compensating for your handholding shakiness and has "swung" all the way to one side, so to speak.
What I am getting at, is that especially with wide-angle image-stabilized lenses, you can end up with random corner or side blurriness issues on some images if you happen to take a photo right when the lens' IS optical group happens to be near its max deflection. For whatever reason, the EF-S 15-85mm does not suffer from that issue all that much. Also, most telephoto IS lenses seem relatively impervious to the problem as well.
Lastly, I recently did some experiments with a Canon 12.5mm extension tube and was quite surprised at what an effective macro lens the EF-S 15-85mm turns out to be. Certainly the working distance is not great and you'd be better off investing in a real macro lens if you do a lot of close-up photography, but if you are trying to travel light and not bring along an extra lens, a tiny and lightweight extension tube might just be the ticket.
So in conclusion, if you own a 1.6x crop sensor Canon body, like a Rebel, an EOS-40D or even an EOS-7D, I'd say you should have a close look at this lens if you want an all-in-one "travel" or "walk-around" zoom. While its range might not be quite as appealing as the EF-S 18-200mm for example, its image quality is way higher and with a 24mm equivalent wide-angle end, it is also as wide as many people will ever want to go. Personally I don't find a 28mm equivalent focal length, 18mm on a crop body, wide enough for really dramatic perspective shots either.
Lastly, I love shooting with a sharp image-stabilized wide-angle lens on a camera body that can give clean high ISO results, like the EOS-7D. It feels liberating to be able to take photos at night, without the need of a tripod, and know the quality is still there should I want to make bigger prints from those images.
We generally keep this lens in stock at Beau Photo and we also rent it, so check it out some time!