Just a bit of input. I struggled last month over whether to buy the Nikon 105mm VR or the Sigma 105mm OS and decided after reading numerous reviews to buy the Sigma for my D800. I have not regretted so far it and hope to really put it through its paces when the spring arrives.
Both those macro lenses are very sharp. The advantage of the Nikkor is that its dimansions are fixed and it focuses internally (the rear element moves inside) whereas the on the Sigma, IIRC, front element moves in and out when you focus.
This has implications for macro work where the front of the lens approaches or retreats from your subject while focusing. This can disturb subjects such as insects when working at very close distances.
> on the Sigma, IIRC, front element moves in and out when you focus.
This was true of the older Sigma 105/f2.8 EX DG AFD, but as Richard says, is NOT true of the new 105/f2.8 EX HSM OS. The new model is at full parity with the Nikkor for all of the major features (flexible focusing, stabilixation, internal focus design, 1:1 reproduction) and at least parity optically. Unfortunately, as Sigma's quality and designs have improved, their prices have increased considerably, and this particular Sigma actually costs more than the Nikkor equivalent.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!
Price was never the deciding factor, but technology was. Reading all the reviews the Sigma came out a least equal, if not ahead of the Nikon 105mm. We are fortunate in the UK as the Sigma is actually $100-150 less than the Nikon too, an added bonus
I actually bought the Metz ring flash to go with it and I am hoping it will be a good combination. I chose Metz as it was lightweight, no leads and 50% cheaper than the Nikon kit. I have had the Sigma ring flash before and found it heavy.