Sigma 180mm f2.8 Macro OS, the Macrosaur (field test/review )

 

Conclusion.
The  Sigma 180mm f2.8 Macro is known to be very good  for protrait and as a general telephoto, but it is really exciting for macro, the only little (no pun intended) flaw being the size and weight, and the humongous hood (which is better to take off when shooting at insect and other critters). With repect to the recently discontinued but really good Sigma 180mm f3.5 Macro EX, the  new  180 f2.8 OS has a better contrast a faster af and obviously the image stabilization (with said limitations at high reproduction ratios).
In comparison with the 200mm f4 AfD ED Micro-Nikkor, the new Sigma has roughly the same image quality (with different colour nuanches, the nikon is more "punchy", while the Sigma is somewhat more delicate), but bokeh is better for the Sigma (with the micro nikkor bright out of focus spots made circles often with jagged edges, due to diaphragm blades, while with 180 Sigma they are perfectly rounded). Technically, the Sigma is superior for the Autofocus and the stabilization.  
As written above  the Sigma 180mm f2.8 macro OS has many applications  beyond macrophotography, yet it maintains excellent performance also in macro. The  200 micro-nikkor AfD instead is somewhat less versatile, but more "portable", and more  "macro oriented", better suited for manual focusing on a tripod (but not for free-handed manual focus).  
 

 

Mating Sympetrum, taken on a tripod, not an easy task since they changed their perching several times.

 
A big plus of the Sigma toward the 200 micro nikkor AfD is the possibility to mount a dedicated 1.4x converter that balances the reduction of the actual focal lenght with virtuyally no loss in image quality I tried this combo on the  Sigma 180 f 3.5 EX and image quality was nearly indistiguishable from that of the lens alone. The only drawback being  af limited range from infinity to   60-70cm, at shorter distance the lens plus converter becomes manual-focus only.
Finally weight and size may be a hinder for someone (not for me) and make the equally excellent  
Sigma 150 f2.8 OS, an acceptable  compromise between focal length and portability.
But  for me the only real drawback of that 180 Sigma is that I had to return it to the owner!
 
Silvio Renesto