The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF 800mm F11 and the Sigma 120-400mm F4.5-5.6 DG HSM 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 F11 is the longer of the two lenses at 281mm. The Sigma 120-400mm F4.5-5.6 DG HSM with a length of 203mm, is 78mm shorter. Besides being longer, the Canon RF 800mm F11 also has a larger diameter of 102mm compared to the Sigma 120-400mm F4.5-5.6 DG HSM'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 RF 800mm F11 weighs 1260g, which means it is 380g (23%) lighter than the Sigma 120-400mm F4.5-5.6 DG HSM which has a weight of 1640g.
Filter Threads
The Canon RF 800mm F11 has a filter size of 95mm whereas the Sigma 120-400mm F4.5-5.6 DG HSM 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 95mm filters that we recommend you to consider for the Canon RF 800mm F11:
And these are the 77mm filters that we recommend for the Sigma 120-400mm F4.5-5.6 DG HSM:
Lens Mounts
The Canon RF 800mm F11 has the Canon RF lens mount whereas the Sigma 120-400mm F4.5-5.6 DG HSM has the Sony Alpha 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 Sony A99 II, Sony A68 and Sony A77 II for the Sony Alpha Mount.
Sigma 120-400mm F4.5-5.6 DG HSM is also available in Pentax KAF3 mount.
Focal Range
Canon RF 800mm F11 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 Sigma 120-400mm F4.5-5.6 DG HSM has a focal range of 120-400mm and 3.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 180 - 600mm.
