
I think sometimes it's a bit overexagerrated, but Tamron and Sigma both have had some QC issues. I've only bought one Tamron and been happy with that but I've had a few Sigmas with issues. Sigma do seem to be getting their act together though, especially with their art lenses.Is there such a thing as a bad copy of the Nikon lens? I don't see the point in running the risk of getting a dodgy Tamron or Sigma but the phrase 'good/bad copy' is used a lot. How common is it to get a duff one?