p.1 #1 · Sigma 17-35mm DG EX HSM vs Canon 18-55 Samples
A month or so ago I modified an 18-55 for use on my 10D. This was meant as a stop-gap measure until I could purchase a higher end wide zoom lens.
After finally getting enough money for such a lens the search narrowed down to the Canon 17-40, Tamron 17-35 and the Sigma 17-35 EX DG HSM (aka Sigma Alphabet Soup Wide :-). Based on my tight budget I concentrated on the former two lenses. I was swayed by the HSM and better feel of the Sigma lens.
When I got it home I ran some tests on my Canon 18-55, new Sigma 17-35, and Canon 24-85 (Silver ed) at 18mm, 24mm, 35mm and 55mm. At each of these lenghts I shot at fPredicatable at 24, 35 and 55, with the Canon 24-85 looking best at f4-5.6 (depending on the focal length) and f8 in my messy office using halogen lighting.
The best results at all the lenghts, except for 18mm, were best from the Canon 24-85 - no suprise here. The 18-55 did surprising well at all of these focal lenghts except for the corners at 18 (even at f8). However the real surprise was the Sigma - it was a DOG. At all lengths (18,24,55) and aperatures the center of the Canon 18-55 was MUCH better than the Sigma both in sharpens and in contrast. The corners of the Sigma were better than the Canon at 18mm (both at f4 and f8), but were very similar in 24 and 35mm shots at both aperatures.
Now I'm baffled if this Sigma is a lemon and I should try another one, or if my Canon 18-55 is fantastic and I should just use it (probably not due to the soft corners), or if I need to save some more bucks and go for the Canon 17-40 (of which I've heard mixed reviews).
For your viewing pleasure here are samples taken from the Canon 18-55 and Sigma 17-35 at 18mm and f4.0. The results were very similar at f8 as well as at the other focal lengths were the Canon's corners improved.
Canon 18-55 full shot (reduced) - (even reduced I think the Canon is cleary better)
p.1 #3 · Sigma 17-35mm DG EX HSM vs Canon 18-55 Samples
I really cannot see why the Canon is better than the Sigma, let alone head and shoulders better than the Sigma? IMO the Sigma is better, the edge photo concurs that, the centre seems to be better from the Canon, but I hate that greyish cast with the Canon one. IMO Sigma is better in this particular test.
p.1 #4 · Sigma 17-35mm DG EX HSM vs Canon 18-55 Samples
I'm using the 18-55 on my 10D too, and I've been pleasantly surprised by the quality of this lens. If only it was a bit faster and better constructed...
p.1 #5 · Sigma 17-35mm DG EX HSM vs Canon 18-55 Samples
Gilles-27,
The Sigma is MUCH. MUCH softer that the Canon in the center. The situation is so bad that even with a Photoshop USM 2.0 pixels. 100%, the sigma is still much softer and starting to develop a lot of artifacting.
The corners are obviously better at f4.0, almost the same at f8.0.
As far as color cast. The Sigma is clearly warmer, maybe too warm, maybe just right. Can't tell from this lighting situation. But the total lack of center sharpness and contrast kills the lens for me. It's an odd combination the center seems to be no sharper at all than the corners.
All in all I'm hoping this is a flawed lens sample (as opposed to a flawed lens line) since I love the feel of the lens. The HSM is very nice and the focus and zoom dampening/motion is fantastic.
p.1 #6 · Sigma 17-35mm DG EX HSM vs Canon 18-55 Samples
well, a week and a half ago i had a brand new sigma 17-35 ex dg in my house. after about 2 hours of shooting and observing at he resulting images from my 1Ds it was carefully repacked and returned to B&H. i was hoping that sigma had learned from the previous version. for use with my camera it seems they had not. it was immediately replaced with the canon 17-40 L and there is quite a difference. the sigma was real sharp in the center at f8. at 17mm f4 it was less then useable. the edges were as soft as i've ever seen. forget f2.8. an extra $200 was worth the effort. the canon won hands down all the way down to f4. i only wish i could have saved the money and the sigma performed better then it did.
p.1 #8 · Sigma 17-35mm DG EX HSM vs Canon 18-55 Samples
With how poor the center looks, I suspect that this lens is front or back-focusing.
The edge crop looks sharper than the center, since it is so much in of the focus point, it may be front-focus.
p.1 #9 · Sigma 17-35mm DG EX HSM vs Canon 18-55 Samples
ding, ding, ding
We have a winner. Mike is right.
At first I had discounted front-focusing because the computer box in front of the focus box was still soo very soft, Well it turns out it is probably focusing even in front of that.
I re-took the shots first in AF (lens showed about 6 feet, target is at least 15), then I manually inched forward in 4 steps towards infinity. The second shot was the sharpest - looks rather nice.
I then snapped a few shots of my computer keyboard at several focal lenghts at a 45 degree angle with the keyboard filling the image - each time I focused on the "U" key, when reviewing the images the sharpest key was "R" or "T" keys, in each case 2 or 3 keys in front of the actual focus point.
So the question is, is this a problem with all the Sigmas or just the one I was lucky enough to get. I'll swap it, hopefully the vendor will not balk and post results here.
