Canon EF-S 15-85mm f/3.5-5.6 USM IS - Review / Lens Test Report
Lens Reviews -
Canon EOS (APS-C)
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The Canon EF-S 15-85mm f/3.5-5.6 USM IS is one of the more promising lenses released for Canon APS-C DSLRs. So far Canon had a bit of a problem regarding their EF-S standard zoom lenses. The current EF-S 18-55mm IS kit zoom lens is pretty good and there's, of course, the EF-S 17-55mm f/2.8 USM IS but this is where the glory ends. All long range standard zooms fell clearly short of the competition especially when looking at the corresponding products from Nikon. The EF-S 15-85mm has a 5.6x zoom ratio and a field-of-view equivalent to 24-136mm in full format terms - obviously a quite ambitious design albeit a "slow" one. As such it competes against impressive competitors a la Nikkor AF-S 16-85mm f/3.5-5.6 VR (Nikon) and Zeiss 16-80mm f/3.5-4.5 (Sony Alpha). It's certainly an interesting crusade especially because the Canon lens is (currently) more expensive at around 750€/800US$.
Over the recent years we often criticized Canon regarding the rather mediocre build quality in some of their consumer lenses like e.g. the Canon EF-S 17-85mm f/4-5.6 USM IS. Fortunately we can report that the EF-S 15-85mm IS has been improved in this respect. It's still a plastic construction (just like the higher priced EF-S 17-55mm f/2.8 USM IS) but the quality of the used materials is actually very good. There aren't really any wobbling parts anymore and that's despite the duo-cam design (two inner lens tubes) which is used to extend the lens when zooming towards the long end of the range. The two control rings are tight and operate pretty smooth. The front element does not rotate so using a polarizer remains easily possible. It is a bit unfortunate that Canon does not provide a lens hood in the standard package but it's not surprising either because they're only doing so for their L class lenses regardless of the price of a lens.
Typical for medium- to high-end Canon lenses the AF is driven by a ring-type USM ("Ultrasonic Motor") which provides very fast and virtually silent AF operations. Full time manual focusing is always possible in one-shot AF mode. The AF accuracy was pretty good on our test body. The AF speed in contrast AF mode (aka LiveView) is slow.
Another mainstream feature is the image stabilizer with a claimed efficiency of up to 4 f-stops. While this may be possible in lab conditions we'd recommend to avoid exploiting this to the max due to the increasing number of outliers in field conditions.
|Equiv. focal length||24-136mm (full format)|
|Equiv. max. f-stops||f/5-8 (full format, in terms of depth-of-field)|
|Optical construction||17 elements in 12 groups inc. 3x aspherical and 1x UD elements|
|Number of aperture blades||7 (circular)|
|min. focus distance||0.35m (max. magnification 1:5 @ 85mm)|
|Hood||optional, petal-shaped, snap-on type|
|Other features||IS (Image-Stabilizer) with tripod detection|