The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 100-400mm f4.5-5.6L IS USM and the Canon EF 400mm F2.8L IS III 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 EF 400mm F2.8L IS III USM is the longer of the two lenses at 343mm. The Canon 100-400mm f4.5-5.6L IS USM with a length of 189mm, is 154mm shorter. Besides being longer, the Canon EF 400mm F2.8L IS III USM also has a larger diameter of 163mm 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 100-400mm f4.5-5.6L IS USM weighs 1380g, which means it is 1460g (51%) lighter than the Canon EF 400mm F2.8L IS III USM which has a weight of 2840g.
Filter Threads
The Canon 100-400mm f4.5-5.6L IS USM has a filter size of 77mm whereas the Canon EF 400mm F2.8L IS III USM has a 52mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Canon 100-400mm f4.5-5.6L IS USM:
And these are the 52mm filters that we recommend for the Canon EF 400mm F2.8L IS III USM:
Lens Mounts
Both the Canon 100-400mm f4.5-5.6L IS USM and the 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 Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K.
Focal Range
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.
On the other hand, the 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 a 35mm (FF) equivalent of 640mm.
