The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 800mm F5.6 EX DG HSM and the Canon 800mm f5.6L IS 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 800mm F5.6 EX DG HSM is the longer of the two lenses at 521mm. The Canon 800mm f5.6L IS USM with a length of 461mm is 60mm shorter. On the other hand, the Canon 800mm f5.6L IS USM has a larger diameter of 163mm compared to Sigma 800mm F5.6 EX DG HSM's 157mm 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 800mm f5.6L IS USM weighs 4500g, 8% (400g) lighter than the Sigma 800mm F5.6 EX DG HSM's weight of 4900g.
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 800mm F5.6 EX DG HSM and Canon 800mm f5.6L IS 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 800mm F5.6 EX DG HSM is also available in Nikon F (FX) and Sigma SA mounts.
Focal Range
Both lenses have the same focal range of 800mm and the fastest aperture of F5.6.