The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon EF 400mm F2.8L IS III USM and the Canon 16-35mm f4L 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 EF 400mm F2.8L IS III USM is the longer of the two lenses at 343mm. The Canon 16-35mm f4L IS USM with a length of 113mm, is 230mm shorter. Besides being longer, the Canon EF 400mm F2.8L IS III USM also has a larger diameter of 163mm compared to the Canon 16-35mm f4L IS USM's 83mm 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 16-35mm f4L IS USM weighs 615g, 78% (2225g) lighter than the Canon EF 400mm F2.8L IS III USM's weight of 2840g.
Filter Threads
The Canon EF 400mm F2.8L IS III USM has a filter size of 52mm whereas the Canon 16-35mm f4L 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 52mm filters that we recommend you to consider for the Canon EF 400mm F2.8L IS III USM:
And these are the 77mm filters that we recommend for the Canon 16-35mm f4L IS USM:
Lens Mounts
Both the Canon EF 400mm F2.8L IS III USM and the Canon 16-35mm f4L 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.
Focal Range
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.
On the other hand, the Canon 16-35mm f4L IS USM has a focal range of 16-35mm and 2.2X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 25.6 - 56mm.