The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 500mm F4 DG OS HSM Sport and the Canon EF 400mm F2.8L IS III 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.Sigma 500mm F4 DG OS HSM Sport is the longer of the two lenses at 380mm. The Canon EF 400mm F2.8L IS III USM with a length of 343mm is 37mm shorter. On the other hand, the Canon EF 400mm F2.8L IS III USM has a larger diameter of 163mm compared to Sigma 500mm F4 DG OS HSM Sport's 145mm 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 EF 400mm F2.8L IS III USM weighs 2840g, 14% (470g) lighter than the Sigma 500mm F4 DG OS HSM Sport's weight of 3310g.
Below you can find the dimension and weight table of the 'Telephoto Prime Lenses in Canon EF Mount for size comparison purposes.
Telephoto Prime Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both Sigma 500mm F4 DG OS HSM Sport and Canon EF 400mm F2.8L IS III 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 500mm F4 DG OS HSM Sport is also available in Sigma SA and Nikon F (FX) mounts.
Focal Range
Sigma 500mm F4 DG OS HSM Sport is a prime lens with fixed focal lenght of 500mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 800mm.
Canon EF 400mm F2.8L IS III USM is a prime lens with fixed focal lenght of 400mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 640mm.