Summary: Overall, the Canon EF-S 17-85mm f/4-5.6 IS USM lens doesn’t really live up to its promises. The zoom range is excellent but in all other respects there are better alternatives in the Canon stable.
Conclusion: The EF-S 17-85mm is a major step up from Canon’s EF-S 18-55mm F3.5-5.6 II kit lens, adding an extended focal length range, image stabilization, fast and silent autofocus with a decent manual focus option, and substantially improved build quality.
Pros: Decent build quality - much better than any of Canon's 18-55mm kit lenses, Very useful focal length range, almost ideal for a walkaround lens, Highly effective image stabilization, Excellent autofocus and manual override, Consistently high image quality across almost all of the range
Cons: Poor performance at wideangle, with marked barrel distortion, high levels of light falloff, and intense green/magenta chromatic aberration, Slow maximum aperture, Very average close-up performance
Conclusion: I can’t help feeling that Canon have pushed the focal range a tad too far at the wide end of this optic because from the 20mm mark through to the 85mm end it is a cracking walkabout lens. It is only the widest few millimetres that let it down a touch.
Pros: Excellent resolution holds up throughout the focal range., IS system helps a lot in low light., The lens makes a good replacement for kit lenses, The focal range ideal for a walkabout lens.
Cons: Distortion is bad at the widest settings and a little CA creeps in., Front lip is prone to damage., Hood is an optional extra.
Summary: In practice though, the Canon EF-S 17-85mm is a slightly mixed bag. On the upside,
the range is considerably more useful than the basic 3x of the 18-55mm, squeezing
in fractionally more at the wide angle end, and offering far more scope at the
Conclusion: The Canon EF-S 17-85mm f/4-5.6 USM IS is a lens that promises many things. It is certainly a very versatile standard zoom with a long zoom range and an image stabilizer that can save the day in many situations.
Conclusion: I’m a bit confused when writing about this lens. I have to admit that I was thinking about buying this lens but only until we got the test results. Canon seems to use an odd kind of policy, (i.e.
Cons: high level of chromatic aberration at 17 mm focal length, weak picture resolution at 17 mm at the edges of the frame, visible vignetting at 17 mm, very large distortion at 17 mm focal length, weak aperture
Excerpt: De lichtafval van de Canon 17-85mm, uitgedrukt in stops, is bij volle lensopening en (op de Canon 7D) zonder in-camera correctie met name bij de brandpuntafstand 17 mm hoog. Bij de andere diafragma's zal je er in de praktijk zelden last van hebben.
Pros: Tamelijk ongevoelig voor tegenlicht, Effectieve beeldstabilisatie, Gunstig zoombereik
Cons: Hoge vervorming bij 17 mm, Hoge lichtafval bij 17 mm, Laag scheidend vermogen in de hoeken