>>2891047I personally own the Sigma 105mm with HSM and OS and I'm really happy with it. It gives really crisp focus, but might be a little short on a full frame sensor. I own a DX camera myself, so it might be better with a 150 or 180 or maybe a 200mm macro instead.
I haven't tried Nikon's own 105mm, but I know that it is onl marginally better than the one I own, and double the price. The Sigma 150 and 180 are superb as well with little chromatic abberation and little to no distortion. It has more falloff, though, but on a macro lens that isn't really a big issue since the background is blurry anyways and can be easily corrected in post.
If she wants only a macro lens the 200mm would be the best bet, though. I went for the 105 since it can also be used with portraits without issues.
Pic related is a photo from my sigma 105mm.
