This is a great super sharp macro lens. Ideal for product photography or other macro shots where getting close to the subject is desirable. Compared to a non-macro lens, like the 50mm f1.7, the focus is quite slow. It can be used for non-macro photography as long as fast focusing is not required.
There are 3 versions of the f2.8 lens, the original, the RS (restyled) and the “D”. Each one makes incremental improvements or brings new features but all of them are exceptional optically.
The f3.5 version is 1:2 maximum magnification and some consider to be slightly sharper.