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Canon EFS 17-85 f/4-5.6 vs. EF 17-40L f/4 shoot out

June 21, 2005

I have successfully narrowed down my choices for lenses to these two. A couple of questions remained however, which required me to test the two lenses side by side to answer. The main idea was to decide whether the 17-40 was worth the additional $200, and losing the 45mm in the long end when compared to the 17-85. There have been many people who have said good and bad things about the 17-85, but I got the impression that many negative comments were based on speculation and 'L-itis' rather than a rational examination of what it really offers and to whom. Hence, I set out to answer that for myself. I was really curious about a few things. First if the sharpness or color rendition of the 17-40 was vastly superior to the 17-85. I was also curious as to how the IS felt and performed and how useful it would be. It turns out that Camera Canada has the best price on both of these lenses (687.45 CAD for the IS and 920.00 CAD for the L). The staff at Camera Canada were nice enough to let me come in with a camera and take a slew of pictures to help me decide.

First Impressions

I don't think I need to say anything about the build and construction of the 17-40L; it was solid and excellent. I was pleasantly surprised with the build of the 17-85 however. After numerous negative comments on the forums, I expected to feel something cheap like the 18-55 kit. However, it seemed to be very well built and felt quite good in my hands. Weight was comparable to the 17-40, and it was slightly shorter.

Both lenses have USM and hence an inner focussing mechanism and full time manual focus. The 17-40 does have the slight advantage of an inner zoom system where as with the 17-85 the barrel extends while zooming. I took a couple of quick shots to get a feel for the AF speed and accuracy of both lenses, I found them to be comparable and quite fast. I also turned on the IS, and to my surprise noticed it was very quiet (unlike the IS on the 70-200L f/2.8 IS).

17-40 f/4L on a 20D
17-85 IS on a 20D


All tests were performed with:
  • Digital Rebel XT (350D) mounted on a tripod
  • ISO 400, RAW, AWB
  • All in camera sharpening and filtering we turned OFF
Some cropping was performed (all images unless otherwise noted at 1:1 pixel size), but no other photoshopping was done (unless otherwise noted).


Left of center crops wide open (f/4) (17mm)
17-85 IS at f/4
17-40L at f/4
17-85 IS at f/4
17-40L at f/4

Wide open, I would say the 17-85 has a slight edge over the 17-, however they really are very close.

Left of center and right of center crops at f/8 (17mm)
17-85 IS at f/8
17-40L at f/8
17-85 IS at f/8
17-40L at f/8

At f/8, we see the 17-40L improves remarkably where as the 17-85 really doesn't, giving the 17-40 the clear advantage.

Left of center and center crops at f/11 (17mm)
17-85 IS at f/11
17-40L at f/11
17-85 IS at f/11
17-40L at f/11

At f/11, we see that the center crop (the one below) seems quite identical, where as in the crop to the side, the 17-40L is still sharper.

Center and left of center crops at f/22 (17mm)
17-85 IS at f/22
17-40L at f/22
17-85 IS at f/22
17-40L at f/22

At f/22, the center and side crops look similar on both lenses.

Center and left of center crops (f/8 and f/22) (40mm)
17-85 IS at f/8
17-40L at f/8
17-85 IS at f/8
17-40L at f/8
17-85 IS at f/22
17-40L at f/22

Moving onto 40mm, we can see that the center crops look very similar on both lenses at f/8. However, the side crop on the 17-85 is noticably soft. It gets much better by f/22.

Chromatic Aberration

Extreme left crop (150% zoomed up) (17mm)
17-85 IS at f/4
17-85 IS at f/8
17-85 IS at f/11
17-85 IS at f/22
17-40L at f/4

As we can see from the side crops, there is siginificantly more CA with the 17-85 at all apertures than there is with the 17-40L. I noticed this CA is present in nearly all 17mm shots near the edges and corners.

Image Stabilizer

IS test, f/5.6 at 1/8 sec shutter at 85mm with low light conditions
NO image stabilizer
WITH image stabilizer

This really is a torture test for the IS. At 85mm, after the 1.6x crop factor, conventional wisdom would indicate the slowest shutter speed to attempt without camera shake to be about 1/125 sec. Canon claims the 3rd generation IS is capable of providing a 3 stop advantage, which brings this down to 1/15 sec. So shooting at 1/8 sec is really pushing it, however the IS still delivered. In this case it means the difference between a photo that is completely useless to one that is can be salvaged with a little bit of filtering (shown below).
WITH image stabilizer and in camera filtering + PTlens + Photoshop

Update (July 7, 2005): I found the Image Stabilizer and absolute boon when doing indoor shooting with this lens. I took several portraits indoors with available light at 1/10 and 1/15 which worked out quite well because of the IS. In the few days I had this lens, I really liked doing portraits with it and found it a joy to use in the 24-85 range.

Distortion and Color

I didn't notice any significant distortion in the images I took. However, after running the image through PTlens, I guess there is a little bit of distortion at 17mm in both lenses (a little bit more distortion in the 17-85), and the 17-85 does have just a slight bit of pin cushioning at 85mm.

Despite the things I have read on the forums, I noticed no real difference in the color rendition. I liked the color rendition of both the lenses, and I think the 17-85 is just subtlely warmer (or alternatively the 17-40 is cooler), which I also like.

Definitely no problems in this department.

Update (July 7, 2005): There is distortion in all focal lengths on the 17-85, severe barrel distortion from 17-24, slight pincushioning from 35-50, and severe pincushioning from 50-85. In contrast, the 17-40L has some slight barrel distortion from 17-24 and no distortion whatsoever from there on. I actually found it annoying to have to have to PTLens my long focal length shots then crop on the shots I took on the 17-85.

The real world

Pixel peeping is fun, and if you pixel peep, it becomes obvious that the 17-40L is an optically superior lens. However most of us aren't going to look at our photos at 100% pixel size, nor are we going to disable all the in camera filtering. Hence the two pictures below. All in camera filtering was turned on (Parameter 1 on the XT), I ran both through PTlens to account for distortion. I also ran the Photoshop Unsharpen Mask filter, removed CA by adjusting magenta levels and sized the originals down by 50% before taking the crops.

After In camera sharpening, color/contrast enhancements, CA correction, PTLens and Photoshop, left of center crop (17mm)

To my eye, the differences are negligible, hence I'm not going to tell you which photo came from which lens, and if you think you know, you might be surprised.


My basic recommendation is this. If you shoot for a living, get the 17-40L, it is optically superior. Going down one stop, you will have tack sharp images from edge to edge with controlled CA. However, if you are looking for a fantastic walkaround/vacation lens with excellent reach, usable low light (through IS) and very good optics but can live with some softness at the corners/edges and some CA, then the 17-85 is it. Remember, you can account for much of the CA and distortion with Photoshop and the 17-85 is excessively soft only in the extreme corners of the image.

I was convinced and orderd my copy of the 17-85. Unfortunately these lenses are in great demand and so there is a back order.

Update (July 7, 2005):
I got a good deal on a 17-40L, and so picked that up instead. No regrets so far, though I do miss having the additional reach. I would still recommend the 17-85 without hesitation as a walkaround/vacation lens.

Kim finally upgraded her 24-85 to the 17-85 IS and so I've managed to shoot a lot with the lens. It is indeed a fine lens and my recommendation for this lens as a great part of a travel kit stands.

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