[speckled wood]

One thing to remember is that many of the cheaper lenses have not been optomised for digital, the actual glass in them is perfectly good but they are designed for 35mm film it is simply that they are not at their best when used on digital cameras, as for build "quality", quality is not the issue it is just that they are not as rugged as more expensive lenses there is no problem if they are treated with respect and not abused and for a lot of people they will be quite adequate until they can afford a more expensive lense.

I do have the 70 to 300 Sigma and to be honest I am not impressed y its macro capabities as well as the problem with the mcrothat happens when I try to switch the macro off. The quality of the macro images (lack of quality) was the reason that I invested in a Sigma 105. The real debate for a serious Macro photographer is not Sigma v Tamrom rather it is whether a shorter or longer focal length is best for you.

SW