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 10-20mm F3.5 EX DC 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 15-35mm F2.8L IS USM is the longer of the two lenses at 127mm. The Sigma 10-20mm F3.5 EX DC HSM with a length of 88mm, is 39mm shorter. Besides being longer, the Canon RF 15-35mm F2.8L IS USM also has a larger diameter of 89mm compared to the Sigma 10-20mm F3.5 EX DC HSM's 87mm 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. Sigma 10-20mm F3.5 EX DC HSM 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 10-20mm F3.5 EX DC HSM 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 10-20mm F3.5 EX DC HSM 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 Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount.
Sigma 10-20mm F3.5 EX DC HSM is also available in Pentax KAF3 , Sony Alpha, Sigma SA and Nikon F (DX) 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 10-20mm F3.5 EX DC HSM has a focal range of 10-20mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 16-32mm when used on a APS-C / DX format camera.