The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF 100-500mm F4.5-7.1L and the Canon 100-400mm f4.5-5.6L 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 RF 100-500mm F4.5-7.1L is the longer of the two lenses at 208mm. The Canon 100-400mm f4.5-5.6L IS USM with a length of 189mm, is 19mm shorter. Besides being longer, the Canon RF 100-500mm F4.5-7.1L also has a larger diameter of 94mm compared to the Canon 100-400mm f4.5-5.6L IS USM's 92mm 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 RF 100-500mm F4.5-7.1L weighs 1365g, which means it is 15g (1%) lighter than the Canon 100-400mm f4.5-5.6L IS USM which has a weight of 1380g.
Filter Threads
Both the Canon RF 100-500mm F4.5-7.1L and the Canon 100-400mm f4.5-5.6L IS USM have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Canon RF 100-500mm F4.5-7.1L has the Canon RF lens mount whereas the Canon 100-400mm f4.5-5.6L IS USM has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Canon R100, Canon R8 and Canon R50 for the Canon RF Mount and Canon 1D X III, Canon 6D MII and Canon 5D MIV for the Canon EF Mount.
Focal Range
Canon RF 100-500mm F4.5-7.1L has a focal range of 100-500mm and
5.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
160 - 800mm.
On the other hand, the Canon 100-400mm f4.5-5.6L IS USM has a focal range of 100-400mm and 4.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 160 - 640mm.