Sigma 150mm F2.8 EX DG OS Macro HSM is an Auto Focus (AF) Macro Prime lens with 35mm FF max sensor coverage. When mounted on a 35mm FF sensor camera, it will give you an FF equivalent focal range of 150mm. With a max aperture of f2.8, this is a fast lens.
This lens features on optical image stabilization which helps capturing sharper images at lower shutter speeds. Sigma 150mm F2.8 EX DG OS Macro HSM is not a weather sealed lens, so you have to be extra careful against rain and dust.