The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 90mm F2.8 Di III 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 a crucial factor to consider when comparing two lenses. Tamron 90mm F2.8 Di III is the longer of the two lenses at 126mm. The Sigma 105mm F2.8 EX DG Macro with a length of 98mm, is 28mm shorter. Besides being longer, the Tamron 90mm F2.8 Di III 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 equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Sigma 105mm F2.8 EX DG Macro weighs 460g, 26% (170g) lighter than the Tamron 90mm F2.8 Di III's weight of 630g.
Filter Threads
The Tamron 90mm F2.8 Di III has a filter size of 67mm whereas the Sigma 105mm F2.8 EX DG Macro has a 62mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Tamron 90mm F2.8 Di III:
And these are the 62mm filters that we recommend for the Sigma 105mm F2.8 EX DG Macro:
Lens Mounts
The Tamron 90mm F2.8 Di III has the Sony E lens mount whereas the Sigma 105mm F2.8 EX DG Macro has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount and Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Tamron 90mm F2.8 Di III is also available in the Nikon Z mount.
Sigma 105mm F2.8 EX DG Macro is also available in Nikon F (FX) , Pentax KAF, Sony Alpha, Sigma SA and Four Thirds mounts.
Focal Range
Tamron 90mm F2.8 Di III 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.
On the other hand, the 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 1.6x crop, it provides a 35mm (FF) equivalent of 168mm.