9 out of 10 points and recommendedbuild quality, colors, contrast, weather sealing with filter, looks greatlacks IS, only F4, lacks reach compared to peers, quality control
I have owned the 17-40L for several years now and I still get goose bumps when I twist the thing onto my 50D. It still feels great and inspires a feeling of confidence. The best things about the 17-40L are the build quality, contrast and colors. There's this very, very fine contrast that meshes with a very real color reproducton that just makes landscape images look so much better. I have tried other non-L lenses and they don't have that same pop. The non-L canon primes do have the sharpness and contrast, but they are missing that special color.reviewed February 12th, 2010 (purchased for $600)
I use this lens to document the national parks and it has held up in the rain, snow, dust and sleet. You can see some of the samples here:
It will take anything you can throw at it. With a filter, the lens become sealed. This is nice when you have your camera protected but not your lens.
The negatives of this lens are the lack of IS, the fact it doesn't extend to 50mm and the F4. There are newer lenses out now that do offer these features for the same price of the 17-40L. However, I have found none of them offer the build quality, full frame capability, weathersealing or the outstadning color reproduction. This is why I continue to keep the 17-40L despite the competition. If I want speed I grab a 1.8 prime. If I want to shoot colorful landscapes from 17-40mm I grab the 17-40L. If I want ultrawide, I grab my Sigma 10-20.
I also experienced some bad focusing issues with my 17-40L when I first received it(new). It went into Canon service once but came back the same. This was when I decided to buy a body with micro AF adjust. I did some tests and found out my 17-40L had poor focus past 30mm, and prime like sharpness at 17mm. With an adjustment of +5, I have found that the lens focuses perfectly now, a compromise between 17 and 40 in IQ.
If you are looking for a high quality lens that feels right in your hands while producing very rich looking landscape shots, the 17-40L is for you. This lens just oozes quality. It may not have all the features of recent lens releases, but it's still the superior lens. The 17-40L and the new Sigma 50 1.4 would make an amazing high quality combo.