. Excellent sharpness between f5.6 and f16, very good even with the 1.4x TC and 2.0x TC
. Good built quality
. Full time manual focus thanks to ultrasonic AF motor
. Excellent price/performances ratio (the Canon’s and Nikon’s equivalents cost almost twice)
. The focal length allows to isolate the subject against a blurred background
. Closest focusing distance of 46cm
Cons
. Lack of weather sealing and so-so painting
. Slow autofocus
. Lack of image stabilization (this is a very minor cons, since this lens is rarely used handheld)
Conclusion
In my opinion, the Sigma 180 is the best lens for macro photography. Some aspects could be improved: a better painting, weather sealing and image stabilizations, useful when you have to shoot handheld, would make it practically perfect. That said, it is one of my preferred lenses, for its image quality and background blur.
I highly recommend this lens to everyone interested in macro photography!