The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 105mm F2.8 EX DG OS HSM and the Canon 100mm f2.8 Macro USM 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 105mm F2.8 EX DG OS HSM is the longer of the two lenses at 127mm. The Canon 100mm f2.8 Macro USM with a length of 119mm, is 8mm shorter. On the other hand, the Canon 100mm f2.8 Macro USM has a larger diameter of 79mm 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. Canon 100mm f2.8 Macro USM weighs 600g, 17% (126g) lighter than the Sigma 105mm F2.8 EX DG OS HSM's weight of 726g.
Below you can find the dimension and weight table of the Macro Prime Lenses in Canon EF Mount for size comparison purposes.
Macro Prime Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both the Sigma 105mm F2.8 EX DG OS HSM and the Canon 100mm f2.8 Macro USM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Sigma 105mm F2.8 EX DG OS HSM is also available in Sigma SA and Nikon F (FX) mounts.
Focal Range
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 1.6x crop, it provides a 35mm (FF) equivalent of 168mm.
Canon 100mm f2.8 Macro USM is a prime lens with fixed focal lenght of 100mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 160mm.