Super compact & 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 & spherical aberration & provides extremely high optical performance from infinity to 11 Macro SLD glass & Super Multi Layer Coating Three SLD (Special Low Dispersion) glass elements provide excellent correction of all types of aberrations & the Super Multi-Layer Coating reduces flare & ghosting This lens has superior peripheral brightness & provides sharp high contrast images even at the maximum apertures Optical Stabiliser Equipped with Sigma’s proprietary OS (Optical Stabiliser) function this lens offers the use of shutter speeds Approx. 4 stops slower than would otherwise be possible F28 large aperture tele-macro lens Tele macro lenses have a greater working distance It is possible to enjoy Macro photography even when you are far from subject This enables you to capture the small animals & insects without disturbing them Very narrow depth-of-field allows selective focusing & less distracting backgrounds Large aperture of F28 is ideal for sports action & indoor photography Hyper Sonic Motor (HSM) with full time manual focus override The HSM (Hyper Sonic Motor) ensures quiet & high speed autofocus as well as full-time manual focus capability Floating Focusing System produces excellent optical performance A floating focusing system moves two different lens groups in the optical system to different positions This system compensates for astigmatic aberration & spherical aberration Since focusing does not change its overall length this lens is easy to hold & use Rounded 9 blade aperture ring This lens has a rounded 9 blade diaphragm creating a smooth blur to the out of focus areas of the image It is also possible to use this lens with Sigma’s optional APO Tele Converters