I own a good piece (Canon - connection, EOS 40D) for two weeks and I'm perfectly happy with it. Laboratory tests so far I could not make any find. But I do not care. The lens is not so made for the laboratory but for practical use. In my case primarily indoors in not too good light. It delivers sharp images. Only at full aperture I can notice a slight blur at the right edge (at 100% view). Due to the large light intensity, short exposure times are possible, connected to the image stabilization - even in low light - exclude camera shake. HSM operates quietly, fast and very reliable. The colors are natural. There is hardly CAs. Note: Only for APS-C. Otherwise there is Randabdunkelungen. Unique recommendation (in spite of the relatively high price).
