The Sigma 105mm f2.8 EX Macro delivers superb, distortion-free images throughout its broad focus range, from infinity telephoto to 1: 1 (life-size) macro, as close as 12.3" without accessories. Its non-rotating front lens group makes it easier to work with polarizing filters and has a focus limiter. A "focus-free" mechanical design allows the lens to auto focus without any interference from the manual focus ring. This makes it easier to hold the lens without affecting the speed or normal operation of the autofocus function. Rugged mechanical construction also makes it durable enough for even the heaviest use required by professional photographers. The Sigma 105mm f2.8 EX Macro features the new deluxe external EX finish. These features and other Sigma optical advances, including an uncommonly broad range of focus, make this an ideal lens for a wide variety of applications, from nature photography to portraits. A handy screw-in type metal sunshade makes it easier to rotate a polarizing filter. 
 
Super Multi Coating reduces flare and ghosting that tends to occur when using digital SLR cameras.

High performance medium telephoto macro lens optimized for digital cameras.

MACRO 105mm F2.8 EX DG allows greater working distance between the lens and subject. High contrast and excellent image quality are made possible in all shooting ranges. This macro lens is ideal for digital SLR cameras as well as film SLR cameras.

Reduces flare and ghost

This new medium telephoto macro lens employs a new design concept for digital SLR cameras. Its new lens power layout produces an excellent optical performance and also reduces flare and ghost. This new lens is designed to reduce the influence of harmful light caused by reflections from the digital image sensor.

An easy to use 105mm medium telephoto lens

MACRO 105mm F2.8 EX DG lens is very suitable for taking pictures in nature and it enables to use of natural light conditions or flash.
The greater working distance of this lens is very advantageous when taking the picture of a flower among the branches or an insect. You do not shake your subject when you want to take its precise details without blurring by using a tripod.
The narrow angle of view is a great aid for simplifying backgrounds and shallow depth of field makes it easier to handle the composition. This lens would have an equivalent field of view of a 178mm telephoto macro lens on a digital SLR camera (when used with the SD10).

Minimum aperture of F45

Depth of field of medium telephoto macro lenses is generally very shallow; however, Sigma, Canon and SONY mounts of this lens have a minimum aperture of F45 (or F22 for FOUR THIRDS or F32 for Nikon and Pentax mounts) for incredible depth of field.

Screw-in lens hood

A screw-in hood is included, for convenient use of circular polarizing filters. It is possible to attach a 77mm filter in front of the lens hood.

Dual Focus (DF) system

This lens also incorporates a Dual Focus (DF) system that is designed to make the lens easy to hold during auto focusing. The large focus ring offers smooth and positive action whilst focusing manually.