The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 50-500mm F4.5-6.3 DG OS HSM and the Canon 300mm f4.0L IS USM 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. Canon 300mm f4.0L IS USM is the longer of the two lenses at 221mm. The Sigma 50-500mm F4.5-6.3 DG OS HSM with a length of 219mm, is 2mm shorter. On the other hand, the Sigma 50-500mm F4.5-6.3 DG OS HSM has a larger diameter of 104mm compared to the Canon 300mm f4.0L IS USM's 90mm 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. Canon 300mm f4.0L IS USM weighs 1190g, 39% (780g) lighter than the Sigma 50-500mm F4.5-6.3 DG OS HSM's weight of 1970g.
Filter Threads
The Sigma 50-500mm F4.5-6.3 DG OS HSM has a filter size of 95mm whereas the Canon 300mm f4.0L IS USM has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 95mm filters that we recommend you to consider for the Sigma 50-500mm F4.5-6.3 DG OS HSM:
And these are the 77mm filters that we recommend for the Canon 300mm f4.0L IS USM:
Lens Mounts
Both the Sigma 50-500mm F4.5-6.3 DG OS HSM and the Canon 300mm f4.0L 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 50-500mm F4.5-6.3 DG OS HSM is also available in Pentax KAF3 , Sony Alpha, Sigma SA and Nikon F (FX) mounts.
Focal Range
Sigma 50-500mm F4.5-6.3 DG OS HSM has a focal range of 50-500mm and
10.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
80 - 800mm.
On the other hand, the Canon 300mm f4.0L IS USM is a prime lens with fixed focal lenght of 300mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 480mm.