The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 180mm f3.5L Macro USM and the Canon 100mm f2.8 Macro USM for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Canon 180mm f3.5L Macro USM is the longer of the two lenses at 187mm. The Canon 100mm f2.8 Macro USM with a length of 119mm is 68mm shorter. Besides being longer, the Canon 180mm f3.5L Macro USM also has a larger diameter of 83mm compared to Canon 100mm f2.8 Macro USM's 79mm diameter.
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, 44% (490g) lighter than the Canon 180mm f3.5L Macro USM's weight of 1090g.
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 Canon 180mm f3.5L Macro USM and 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.
Focal Range
Canon 180mm f3.5L Macro USM is a prime lens with fixed focal lenght of 180mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 288mm.
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 an 35mm (FF) equivalent of 160mm.