Canon EF-S 17-85mm f/4-5.6 USM IS - Review / Test Report
Lens Reviews - Canon EOS (APS-C)

Review by Klaus Schroiff, published October 2005

Special thanks to Marcus Erne for providing a second sample for testing!


The Canon EF-S 17-85mm f/4-5.6 USM IS is one of the more interesting consumer standard zoom lenses in the market. It is often considered as an upgrade path from the basic EF-S 18-55mm f/3.5-5.6 kit zoom. Obviously it adds quite a bit of range, a 2nd generation image stabilizer and a ring-type USM drive with full-time manual focusing ... at a price naturally. The EF-S naming refers to Short-backfocus design which is only compatible to APS-C EOS SLRs starting with the EOS 300D (Digital Rebel). EF-S lenses have a protruding rear element which requires a special mirror design to avoid a collision of mirror and the rear part of the lens. The principal idea is the reduce the distance of lens to the sensor which can translate to a better lens design - on paper at least.

On Canon APS-C DSLRs such as the EOS 350D (used for testing) its zoom range is equivalent to ~27-136mm (5x ratio) on full frame cameras so it can be considered as an allround zoom lens. Its first obvious drawback is the rather slow max. aperture resulting in very limited creative potential regarding depth-of-field aspects. Same goes for low light potential but the image stabilizer (IS)is capable to overcome this to a certain degree. The 2nd generation IS allows safe hand-holding at speeds up to three stops slower than otherwise possible. Remember that slow shutter speeds can have negative side effects regarding moving objects (motion blur) so IS is not the holy grail of photography but nonetheless it is still highly desirable.

As you can see in the product shots above the lens extends during zooming being shortest at 17mm and reaching its max. length at 85mm. It has a so-called duo-cam zoom system with two inner lens tubes. The lens construction is made of 17(!) elements in 12 groups including 3 aspherical elements. Its aperture mechanism features 6 circular aperture blades. At a size of 79x92mm and 475g it is relatively compact but it is quite a sight when extended to 85mm with attached lens hood.

Regarding its rather high price tag the build quality isn't overly impressive with a couple of squeaking parts and slightly wobbling duo-cams. The plastic shell feels somewhat thin. The zoom and focusing action is quite decent. All-in-all the construction quality is surely better than the EF-S 18-55mm f/3.5-5.6 but this is nowhere near L class quality. As usual the lens has been loaned by a kind OpticalLimits reader so the tested sample has seen the field already. The lens has a tendency to collect dust into the inner chamber.

The lens has a very fast and near silent USM (ultrasonic) AF drive including full-time manual focusing (FTM) in one-shot AF mode. The minimal focus distance is 0.35m resulting in a max. magnification of 1:5 at 85mm. The front element does not rotate so using a polarizer is no problem.

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