TestsAll tests were performed with:
Wide open, I would say the 17-85 has a slight edge over the 17-, however they really are very close.
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.
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.
At f/22, the center and side crops look similar on both lenses.
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.
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.
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).
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 ColorI 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 worldPixel 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.
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.
ConclusionsMy 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.
Hosted by theorem.ca
All text and images (c) 2000-2014 Aravind Krishnaswamy. All rights reserved.