Blurryeyed wrote:
You're not going to gain very much, if you really want a large working distance you may consider the Sigma 180 or the Nikon 200, but you have to realize that these are big, long, and heavy. Comparing the features of the two lenses I would definitely go with the Sigma.
I use a Tamron 180 F3.5 and a Sigma 150 F2.8 - both macro, and I think they are every bit as good as the Nikkors. Build quality is better on the Nikkor, but the optical quality is quite good on all of them. I think all of these are internal focus design, which in the 3rd party lenses means that you won't see the same angle of view as the stated focal length would indicate - I think the Sigma drops down to around 105mm, and the Tamon about 140mm - you still get the full magnification of 1:1, but you will need to be a little closer than you'd expect in order to get that. A minor point that really doesn't hurt your image, in any case.