The lens has a mixture of high quality plastic and aluminium body. It is a comparably compact lens with a metal mount and a silent, fast autofocus. Being a small telephoto lens with a focal length equivalent of 75mm one of its purposes is portrait shots.
Wide open the lens is rather soft but stopping down to f/5.6 yields very sharp results. That way portraits shot wide open render soft with a very nice bokeh.[3]
Distortion is very low and vignetting negligible, but the culprit of this lens is chromatic aberration which is very strong wide open and becomes acceptable only by stopping down towards f/5.6.[4][5]
