The Sigma 105mm f/2.8 Macro lens is a large aperture macro lens giving full 1=1 magnification, also with a rounded 9-blade diaphragm for added smoothness to defocused areas of the image. It is equipped with Sigmaʼs Optical Stabiliser (OS) which corrects for up to 4 stops of camera shake, allowing for hand- holding in most instances.

Optically the lens uses SLD (Special Low Dispersion) glass to correct chromatic aberration, spherical aberration and field curvature, giving superb sharpness, extra low colour aberration and very low distortion levels.

The 142mm close focus gives true macro reproduction but at a longer working distance so there are no camera or lens (or photographer)shadows over the subject and less chance of disturbing living subjects such as insects.

There is also a shallower depth of field for the same macro subject when compared to Sigma macro lenses of shorter focal length such as their 50mm or 70mm versions.