The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 90mm f2.8 Macro and the Sigma APO 180mm F2.8 EX DG OS HSM 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. Sigma APO 180mm F2.8 EX DG OS HSM is the longer of the two lenses at 204mm. The Tamron 90mm f2.8 Macro with a length of 97mm, is 107mm shorter. Besides being longer, the Sigma APO 180mm F2.8 EX DG OS HSM also has a larger diameter of 95mm compared to the Tamron 90mm f2.8 Macro's 72mm 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. Tamron 90mm f2.8 Macro weighs 405g, which means it is 1235g (75%) lighter than the Sigma APO 180mm F2.8 EX DG OS HSM which has a weight of 1640g.
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 Macro and the Sigma APO 180mm F2.8 EX DG OS HSM 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 Macro is also available in Canon EF , Nikon F (FX) and Pentax KAF mounts.
Sigma APO 180mm F2.8 EX DG OS HSM is also available in Canon EF , Nikon F (FX) and Sigma SA mounts.
Focal Range
Tamron 90mm f2.8 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 APO 180mm F2.8 EX DG OS HSM is a prime lens with fixed focal lenght of 180mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 270mm.