Sigma 120-400 APO OS, one of two new lenses by sigma for wildlife that are selling like hot cakes.

This is slightly smaller and lighter that the 150-500 OS and slightly cheaper.
This telephoto zoom lens incorporates Sigma’s original OS (Optical Stabilizer) function. It offers the use of shutter speeds approximately 4 stops slower. Three SLD (Special Low Dispersion) glass elements provide excellent correction for chromatic aberration.

This lens is equipped with the rear focus system that minimizes fluctuation of aberration caused by focusing. It provides optimum image quality throughout the entire zoom range. The super multi-layer coating reduces flare and ghosting. High image quality is assured throughout the entire zoom range.

The minimum focusing distance of 150cm (59.1inch) throughout the entire zoom range and has a maximum magnification of 1:4.2 make it useful for close-up photography.

This lens incorporates HSM (Hyper Sonic Motor), which ensures a quiet and high-speed AF as well as full-time manual focusing capability.

Specifications -

Lens Construction - 21 Elements in 15 Groups
Angle of View - 20.4 - 6.2 degrees
Number of Diaphragm Blades - 9 Blades
Minimum Aperture - F22
Minimum Focusing Distance - 150cm / 59.1 in.
Maximum Magnification - 1:4.2
Filter Size - Diameter 77mm
Filter Size - Bayonet-type Hood
Dimensions - Diameter 92.5mm X Length 203.5mm 3.6 in. X 8 in.
Weight - 1750g/61.7 oz.