7 blades stepping down to f/32.
f/2.8: This lens is ok wide open with good contrast and just a little soft with a bit of Chromatic Aberration. The lens sharpens up a bit from f/3.5 on.
f/8: The lens is very sharp with great contrast.
The bokeh is a little distracting circles but not too bad.
There is very little if any distortion.
This lens is great for doing macro work and even decent portraits. Built like a tank, good pocket lens, really sharp photos stopped down.
One thing to be aware of is that this is a body driven focus system to run the Auto Focus so it will loose auto focus on the armature Nikon bodies.
Skip this lens because for the same price you can buy the superior updated D version for the same price which is incredibly better then this non D version. If you can spend a bit more money and are very serious about macro photography you might want to look at getting a lens with a longer focal length over 100mm. Reason being is that if your shooting bugs and critters you might scare them away with the 60mm being so close. However shooting non moving subjects this lens is great.