The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 24-35mm F2 DG HSM A 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. Sigma 24-35mm F2 DG HSM A is the longer of the two lenses at 123mm. The Sigma 20mm F1.8 EX DG RF with a length of 90mm, is 33mm shorter. On the other hand, the Sigma 20mm F1.8 EX DG RF has a larger diameter of 89mm compared to the Sigma 24-35mm F2 DG HSM A's 88mm 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 20mm F1.8 EX DG RF weighs 520g, 44% (421g) lighter than the Sigma 24-35mm F2 DG HSM A's weight of 941g.
Filter Threads
Both the Sigma 24-35mm F2 DG HSM A 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
Both the Sigma 24-35mm F2 DG HSM A and the Sigma 20mm F1.8 EX DG RF has the same Sigma SA lens mount. Some of the latest released cameras that are compatible with the Sigma SA lenses are Sigma Quattro, Sigma Quattro H and Sigma SD1 Merrill.
Sigma 24-35mm F2 DG HSM A is also available in Canon EF and Nikon F (FX) mounts.
Sigma 20mm F1.8 EX DG RF is also available in Canon EF , Nikon F (DX), Pentax KAF and Sony Alpha mounts.
Focal Range
Sigma 24-35mm F2 DG HSM A has a focal range of 24-35mm and
1.5X zoom ratio .
On the other hand, the Sigma 20mm F1.8 EX DG RF is a prime lens with fixed focal lenght of 20mm.