The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF 800mm F5.6L 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 RF 800mm F5.6L is the longer of the two lenses at 432mm. The Canon EF 400mm F2.8L IS III USM with a length of 343mm, is 89mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 163mm.
Below you can find a scaled side-by-side image of Canon RF 800mm F5.6L and Canon EF 400mm F2.8L IS III USM to get a better idea of how their sizes compare in real life.
Comparison image of the Canon RF 800mm F5.6L and the Canon EF 400mm F2.8L IS III USM Size and Weight 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 EF 400mm F2.8L IS III USM weighs 2840g, 9% (300g) lighter than the Canon RF 800mm F5.6L's weight of 3140g.
Filter Threads
Both the Canon RF 800mm F5.6L and the Canon EF 400mm F2.8L IS III USM have the same Filter thread size of 52mm .
Below are links to the 52mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Canon RF 800mm F5.6L has the Canon RF lens mount whereas the Canon EF 400mm F2.8L IS III USM has the Canon EF lens mount . Some of the latest released cameras that are compatible with these mounts are Canon R6 V , Canon R6 III and Canon C50 for the Canon RF Mount and Blackmagic URSA 12K LF , Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Focal Range
Canon RF 800mm F5.6L is a prime lens with fixed focal lenght of 800mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
1280mm .
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 .
