The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 800mm f5.6L IS USM and the Canon 500mm f4.0L 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 800mm f5.6L IS USM is the longer of the two lenses at 461mm. The Canon 500mm f4.0L IS USM with a length of 387mm, is 74mm shorter. Besides being longer, the Canon 800mm f5.6L IS USM also has a larger diameter of 163mm compared to the Canon 500mm f4.0L IS USM's 146mm 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 500mm f4.0L IS USM weighs 3870g, 14% (630g) lighter than the Canon 800mm f5.6L IS USM's weight of 4500g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Canon EF Mount for size comparison purposes.
Super Telephoto Lenses in Canon EF Mount for Size Comparison
Filter Threads
Both the Canon 800mm f5.6L IS USM and the Canon 500mm f4.0L IS 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
Both the Canon 800mm f5.6L IS USM and the Canon 500mm f4.0L 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 800mm f5.6L IS USM 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 500mm f4.0L IS USM is a prime lens with fixed focal lenght of 500mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 800mm.