The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF 100-500mm 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 100-500mm is the longer of the two lenses at 208mm. The Sigma 120-400mm F4.5-5.6 DG HSM with a length of 203mm, is 5mm shorter. Besides being longer, the Canon RF 100-500mm also has a larger diameter of 94mm 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 100-500mm weighs 1365g, which means it is 275g (16%) lighter than the Sigma 120-400mm F4.5-5.6 DG HSM which has a weight of 1640g.
Filter Threads
Both the Canon RF 100-500mm and the Sigma 120-400mm F4.5-5.6 DG HSM have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Canon RF 100-500mm has the Canon RF lens mount whereas the Sigma 120-400mm F4.5-5.6 DG HSM has the Pentax KAF3 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 Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF3 Mount.
Sigma 120-400mm F4.5-5.6 DG HSM is also available in Sony Alpha mount.
Focal Range
Canon RF 100-500mm has a focal range of 100-500mm and
5.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
160 - 800mm.
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.
