The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 90mm F2.8 VC 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. Tamron 90mm F2.8 VC Macro is the longer of the two lenses at 117mm. The Sigma 105mm F2.8 EX DG Macro with a length of 98mm, is 19mm shorter. Besides being longer, the Tamron 90mm F2.8 VC Macro also has a larger diameter of 79mm 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, 24% (149g) lighter than the Tamron 90mm F2.8 VC Macro's weight of 609g.
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 Tamron 90mm F2.8 VC 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.
Tamron 90mm F2.8 VC Macro is also available in Nikon F (FX) and Canon EF mounts.
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
Tamron 90mm F2.8 VC Macro is a prime lens with fixed focal lenght of 90mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 135mm.
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.