The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 180mm f3.5 LD Macro and the Sigma 105mm 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. Tamron 180mm f3.5 LD Macro is the longer of the two lenses at 166mm. The Sigma 105mm F2.8 EX DG OS HSM with a length of 127mm, is 39mm shorter. Besides being longer, the Tamron 180mm f3.5 LD Macro also has a larger diameter of 85mm compared to the Sigma 105mm F2.8 EX DG OS HSM's 78mm 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 OS HSM weighs 726g, 21% (194g) lighter than the Tamron 180mm f3.5 LD Macro's weight of 920g.
Below you can find the dimension and weight table of the Macro Prime Lenses in Nikon F (FX) Mount for size comparison purposes.
Macro Prime Lenses in Nikon F (FX) Mount for Size Comparison
Lens Mounts
Both the Tamron 180mm f3.5 LD Macro and the Sigma 105mm F2.8 EX DG OS HSM has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Tamron 180mm f3.5 LD Macro is also available in Canon EF and Sony Alpha mounts.
Sigma 105mm F2.8 EX DG OS HSM is also available in Canon EF and Sigma SA mounts.
Focal Range
Tamron 180mm f3.5 LD Macro 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.
Sigma 105mm F2.8 EX DG OS HSM 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.