Abstract: Canon EF-S 17-85/4-5.6 IS USM Lens Review

Photography - Canon EOS, digital, nature

Canon EF-S 17-85/4-5.6 IS USM Review

Canon EF-S 17-85/4-5.6 IS USM Lens Review

Image Stabilization

The EF-S 17-85/4-5.6 IS USM has Canon's 2nd generation IS. The 1st generation gave up to about 2 stops of stabilization, while 2nd generation gives up to 3 stops. Does it actually work? Well, judge for yourself from the following shots. They were made handheld using and EOS 20D with the EF-S 17-85 set to 85mm. They are both 100% crops from the full image.

Canon EF-S 17-85/4-5.6 IS USM Lens Review

If you take the old rule for 35mm that you can handhold a lens at about 1/(focal length) seconds and translate it to the EF-S 17-85 at 85mm, you have to use the 1.6x multiplier to get to (85 x 1.6) = 136mm. So you'd guess that you could probably handhold the lens at 1/136s. Lets call it 1/125s as the nearest standard speed. One stop down would be 1/60s. Two stops down would be 1/30s. Three stops down would be 1/15s. So if IS really does work as advertised, you should be able to handhold it at 85mm and 1/15s. The results above are at 1/10s, an even more severe test.

Canon EF-S 17-85/4-5.6 IS USM Lens Review

At 17mm you can see a similar result from the 100% crops shown above.   If you assume you'd need 1/30s without IS, one stop would be 1/15s, two stops would be 1/8s, three stops would be 1/4. The above images were shot at 1/2s, an even more severe test. I don't think the shot with the IS on is quite critically sharp, but it's much, much better than with IS off and certainly quite acceptable for a handheld shot at 1/2s. Here's a shot taken at 1/30s (with IS on) for comparison:

Canon EF-S 17-85/4-5.6 IS USM Lens Review
1/30s at 17mm  IS on

I think you'll conclude that IS really does work! Of course getting sharp shots at the limits of handholdability is something of a statistical process. Not all shots will be equally sharp (or unsharp), but IS greatly improves the probability of getting a sharp image.


The EF-S 17-85/4-5.6 IS USM obviously isn't a macro lens, but it does focus down to 35cm at all focal lengths. At 85mm Canon spec the magnification at 0.2x. Below is a shot taken at 85mm and the closest focus distance:

Canon EF-S 17-85/4-5.6 IS USM Lens Review
Maximum magnification. 85mm focal length


The EF-S 17-85/4-5.6 IS USM is quite resistant to flare. In general newer lenses intended for digital use have better optimized coating to reduce internal reflections and flare because back reflections from the sensor surface can cause problems if the light is them reflected back again by the lens.

Flare can also be minimized by the use of a lens hood. If you decide to use a filter on the lens, the use of a high quality multicoated filter can prevent the filter from increasing flare.

NEXT - Part IV - Image Quality

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