Super compact and lightweight large aperture telephoto lens with life size macro capability successor to the apo macro 150mm f28 ex dg hsm introduced to market in october 2004 this new os design offers the latest optical technology a floating focusing system moves two different lens groups in the optical path to different positions this system compensates for astigmatic aberration and spherical aberration and provides extremely high optical performance from infinity to 11 macro sld glass and sup