9 out of 10 points and recommendedSharp @f2.8, good price for the qualityfront focus, a little bit dark
I have been owned this lens for almost a month and using it for a Canon Rebel XT.reviewed January 10th, 2007 (purchased for $400)
What I like about that it is quite useful@ f2.8 throughout the 17mm to 50mm.
IT IS sharp at f2.8 and the best sharpness can be reached @ f5.6 for my copy.
Also I had a chance to have Sigma 18-50 DC EX f2.8 (not macro one) for a week.
I compared them through different tests: Overall, I liked the tamron more.
The tamron had a better control over the distortion and vignetting even at widest angel and better sharpness at borders.
However at center over different focal length it is hard sometimes to say which one is better.
Also, I got a bit better (shallower) DOF for the tamron and as it supposed to be, the better BOKEH was more recognizable at f2.8 and 50mm setting for the tamron copy.
.(But in terms of sharpness the tamron not really performed better than the sigma while the focus was the centre subject).
my tamron copy tends to front focus a bit.(not still a big issue on that, but recognizable specially when I compared to my Canon 50mm f1.8 through the test).
And, the tamron tends to produce a little bit darker image compared to the sigma and canon lens kit EFS 18-55. (exactly at the same aperture and shutter speed setting)
At last, the tamron was noisier. But, not really noticeable yet when I am walking around with it.
Although I ordered mine from a retailer in Japan but it is marked assembled in China on the body of the lens. I checked another copy from a local retailer (Ottawa-Canada)
and it was marked assembled in China as well. So, not really sure yet if there is any difference in quality between those marked clearly "made in Japan" and those
marked as"assembled in China from Chinese and Japanese parts"