The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 400mm f2.8L IS USM and the Canon 200-400mm f4L IS USM Ext 1.4x 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 200-400mm f4L IS USM Ext 1.4x is the longer of the two lenses at 366mm. The Canon 400mm f2.8L IS USM with a length of 349mm, is 17mm shorter. On the other hand, the Canon 400mm f2.8L IS USM has a larger diameter of 163mm compared to the Canon 200-400mm f4L IS USM Ext 1.4x's 128mm 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 200-400mm f4L IS USM Ext 1.4x weighs 3620g, 32% (1750g) lighter than the Canon 400mm f2.8L IS USM's weight of 5370g.
Filter Threads
Both the Canon 400mm f2.8L IS USM and the Canon 200-400mm f4L IS USM Ext 1.4x 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
Both the Canon 400mm f2.8L IS USM and the Canon 200-400mm f4L IS USM Ext 1.4x 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 400mm f2.8L IS 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.
On the other hand, the Canon 200-400mm f4L IS USM Ext 1.4x has a focal range of 200-400mm and 2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 320 - 640mm.