I use this lens on my EOS 350D now almost nine months and am -after initial Schwierigkeiten- more than happy with it! In the beginning I had the familiar problem of Frontfokusses, ie the lens always turned sharply about 20cm before actually targeted motif. This was, particularly at maximum aperture, sometimes catastrophically. The problem was corrected but from Tamron and since then everything fits. The high light intensity (you can draw really good images at full aperture!) To get in many situations around the use of flash, which makes it noticeable in the light mood of the pictures. The image quality is excellent, aberrations are in everyday life as well as non-visible. Besides, photographing test charts or newspapers ... The only "drawback" is, as already mentioned, the AF drive. Yes, it is loud, yes it is slow and yes, if it is very dark or the contrast is too weak it has its problems. For sports photography it is (alone because of the focal length!) Not really suitable. But that's to get over for this price. If I want a perfect lens, I buy a L and accordingly put a few euros out. Whether the 650 more for an image stabilizer (the one at this focal length and light intensity does not really need) and the USM when Canon 17-55mm worthwhile, everyone must decide for themselves. I personally get me for the money rather sometime even an ordinary prime lens with f1.4 USM and because I get more. All in all, the perfect "Always plan", which is more than worth the money and the photographer is a real pleasure and great pictures. Since I mostly take pictures in the studio, I use at the moment absolutely no different lens and brings me out completely.
