The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF 15-35mm F2.8L IS USM and the Sigma 20mm F1.8 EX DG RF 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 15-35mm F2.8L IS USM is the longer of the two lenses at 127mm. The Sigma 20mm F1.8 EX DG RF with a length of 90mm, is 37mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 89mm.
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. Sigma 20mm F1.8 EX DG RF weighs 520g, 38% (320g) lighter than the Canon RF 15-35mm F2.8L IS USM's weight of 840g.
Filter Threads
Both the Canon RF 15-35mm F2.8L IS USM and the Sigma 20mm F1.8 EX DG RF have the same Filter thread size of 82mm.
Below are links to the 82mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Canon RF 15-35mm F2.8L IS USM has the Canon RF lens mount whereas the Sigma 20mm F1.8 EX DG RF has the Canon EF 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 Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Sigma 20mm F1.8 EX DG RF is also available in Nikon F (DX) , Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Canon RF 15-35mm F2.8L IS USM has a focal range of 15-35mm and
2.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
24 - 56mm.
On the other hand, the Sigma 20mm F1.8 EX DG RF is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 32mm.
