Summary: GRAY MARKET LENS First lens I ordered just didn't have the sharpness I thought any lens should provide. I had done a LOT of research prior to purchasing the lens, knowing it was on the cheaper end of most lenses, and had heard that sometimes you can get a 'dud'.
Summary: Some time back I had ordered the Tamron SP AF28-75 F/2.8 Di from Amazon, which was sold directly from Amazon - it came with Tamron's 6-year USA warranty. I recently ordered this lens, which was fulfilled (but not sold) by Amazon.
Excerpt: This one has soft focus and distortion around the edges. Point of focus was not sharp and shutter speed was fast enough to stop any movement. I was also using a medium aperture (f-5.6 - f-8). Lens seemed to have a very shallow depth of field in front of the focus point.
Excerpt: My wife bought one of these for her Canon EOS 60D and it is an excellent lens. So excellent that I bought one for my EOS 60D. It consistently focused six inches behind my chosen focus point, and even at its best focus was not sharp.
Excerpt: I tried this lens based on many positive reviews. In my case the first copy I received was sharp on the right side of the image and very very soft on the left side...decentering. I called B & H and ordered a replacement thinking that I just had bad luck on the lens I was going to return.
I tested out 2 copies of the lenses - Not Satisfied
Nathan Dean, Amazon
9 February 2012
Summary: First off I ordered this lenses because I own the 70-200mm Tamron f2.8 and have been so thrill with the photos I got that I had to give this one a try too. I ordered this lenses in January of 2012 and the first copy I got the quality of the images were good but not great.
Summary: As others have said, I too really wanted to like this Tamron 17-50 lens. I know Tamron makes a good product because I own the Tamron 90mm SP macro lens and use it with my new T3i and it takes some of the most beautiful pictures I have ever taken with any lens.