I was given a 450d with a canon 17-85mm lens, it has USM and image stabilzing. It has always seemed okay to me but after a few years i have decided to upgrade to the 700d, which has now come with a 18-55mm kit lens. This one has STM and also image stabilzation.

I am mostly interested in the wide angle of the lens, so the extra 85-55 doesnt do much for me, and the 18-17 is pretty close for me purposes. What I have noticed though, is that the STM seems to be much more quiet than the USM. Is this STM the upgrade from USM or are they different things?

My question is which one has better image quality on the wide end. I am curious as to why as well, besides for seeing that the 18-55 has a wider aperature, the 17-85 just feels better. The feeling i mean in terms of industrial build quality, it seems to be less fragile. I also see that the end of the lens is over 60mm, not like the 52mm of the kit lens or the other intro lenses such as 55-250mm. Does this size have something to do with it?

4 Answers 4


STM and USM are different kinds of focusing motors. Prior to STM, USM was the preferred option because it was fast and quiet (relative to other kinds of motors that are available). However, it isn't fluid which becomes an issue with video. Enter STM which is also quiet (though I'm not sure which is more quiet) and provides a smooth transition as it focuses rather than a jerky back and forth. My understanding is that USM is still preferred for stills, but STM is preferred for video.

As far as image quality, if you have both lenses available and you can't tell the difference between two pictures that you take, does it matter? I'd recommend looking at sites that review these kinds of things, but Roger Cicala and Lensrentals.com recently compared a couple of lenses and noted that when doing the tests at the wide angle it has to be done near minimum focus distance which is not the typical use case for that focal length. So try for yourself and use which you feel more comfortable with.

  • well i just got the lens, and i couldnt find anyone comparing these two lenses. I could do some studies, but If someone here was more knowledgable on the difference, because they are visibly physically different, I would appreciate the advice so i dont chose an obviously wrong one, or find out after awhile that in specific situations one is better than the other but i never did that test. If i should keep both I will, but if one is overall superior than why keep both Mar 11, 2014 at 14:03
  • You can hear the difference between some STM and USM lenses focusing here (as recorded by in-camera mic). USM generates a lot of start/stop focusing noise as it reaches the focus position, while STM does not, as it reduces the 'jolt' as it starts/stops focussing (probably at the cost of a little AF speed). Not all USM are equal though, some will be much faster/slower than currently available STM. Even the fairly new 85mm f/1.2L II has a rather slow USM. Mar 12, 2014 at 2:16

The current 18-55 IS is a very sharp lens. Optically superior to the 17-85 over the common range. The build quality is not as good, as well as the AF speed and accuracy.

So the 17-85 is an upgrade over the 18-55, but not a big a one. A better choice is the 15-85.

  • if the 18-55 is optically better than 17-85, is the 'upgrade' you speak of just for the focusing and durability? Mar 12, 2014 at 0:28
  • yes and range. It's nice to get out of the "normal" range and get more into the portrait range as well. Mar 12, 2014 at 0:43

According to the Photozone.de, 17-85mm USM is often considered as an upgrade path from the basic EF-S 18-55mm f/3.5-5.6 (not STM) kit lens.

Here is reviews of both lenses:

I don't have either of them, you can compare their specifications on DPReview.com, the 17-85 is wider and has more reach, it also has metal mount, overall it has better build quality, but the new 18-55 STM is lighter and has a new less noisy focus motor which makes ideal for movies, it is also brighter as you mentioned and has better image stabilization.


This is kind of a hard head-to-head comparison, but basically, the EF-S 17-85 was an upgrade over the contemporaneous 18-55 kit lenses of its day (2004)--the non-USM, non-IS first version.

The IS STM version of the 18-55 kit lens, however, is something like the eighth version of that lens, introduced in 2013, so it's a spanking new design, and probably performs quite well in comparison with the decade-older 17-85.

Which is why the EF-S 15-85 IS USM came out in 2009.

The 17-85 IS USM is a more "upscale" lens than an 18-55. If you roughly group the Canon lenses into low/mid/high tiers, then the 18-55 is designed to be a consumer-grade entry-level lens, kitted with bodies. The 17-85 is more in the mid-range of lenses that Canon makes, which are typically characterized by the gold ring and USM. And the high-end tier are the red-ringed L lenses.

None of that necessarily matters a huge deal in terms of image quality (despite all the messageboard hype you will read), especially if you stop down to f/8 and post process. It's mostly about build quality, and usability features. Larger max. apertures, easily used manual focus rings, distance scales, a USM or STM focus motor, stabilization, weather sealing, internal zooming, AF range limit switches, and more exotic glass or correctional elements, etc. etc.

At each tier, you end up with diminishing returns, and much heftier price leaps. Buyer's remorse can bite especially hard with a first L lens purchase, because of inflated expectations (it's still just glass that has to obey the laws of physics) and the (usually) >$1k price tags.

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