Sigma sycophants do not read below. I’ve finally finished my review of the Sigma DC EX 18-50mm F/2.8 macro I started a month ago. It was super soft, so I sent it back (my nickel) to a Sigma repair facility and they claim they repaired the rear lens group. It works much better, vastly improved I’d say. In fact it’s very sharp, even at F/2.8, but the inevitable caveats always seem to appear. This time it’s focusing accuracy. I think with all the new demand for DSLR cameras, and a natural demand for additional lenses, that maybe Sigma, to name one, is running a bit behind schedule, so they simply cobble together a lens and hope it works ok. I’ve never had any trouble in the years past, but this year I’m one for three. I’ve also cancelled my Sigma 100-300 F/4 lens that I ordered from Adorama, it wasn’t their fault, it was Sigma’s for not producing the lens in the time period promised—I waited almost two months.
I’m going to go ahead with the review based on a couple of other reviews I’ve read. I think my copy is about average at this point, and maybe slightly above average in sharpness.
Sigma lens buyers-and all others I suppose-should be aware of performance issues when buying a lens, make sure you check it out before you do any serious photography.