The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony 100mm F2.8 Macro and the Sigma 105mm F2.8 EX DG Macro for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Sony 100mm F2.8 Macro is the longer of the two lenses at 99mm. The Sigma 105mm F2.8 EX DG Macro with a length of 98mm, is 1mm shorter. Besides being longer, the Sony 100mm F2.8 Macro also has a larger diameter of 75mm compared to the Sigma 105mm F2.8 EX DG Macro's 74mm diameter.
The weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Sigma 105mm F2.8 EX DG Macro weighs 460g, 8% (45g) lighter than the Sony 100mm F2.8 Macro's weight of 505g.
Below you can find the dimension and weight table of the Macro Prime Lenses in Sony Alpha Mount for size comparison purposes.
Macro Prime Lenses in Sony Alpha Mount for Size Comparison
Lens Mounts
Both the Sony 100mm F2.8 Macro and the Sigma 105mm F2.8 EX DG Macro has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A99 II, Sony A68 and Sony A77 II.
Sigma 105mm F2.8 EX DG Macro is also available in Canon EF , Nikon F (FX), Pentax KAF, Sigma SA and Four Thirds mounts.
Focal Range
Sony 100mm F2.8 Macro is a prime lens with fixed focal lenght of 100mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 150mm.
Sigma 105mm F2.8 EX DG Macro is a prime lens with fixed focal lenght of 105mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 157.5mm.