The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 20mm F1.4 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 20mm F1.4 DG HSM A is the longer of the two lenses at 130mm. The Sigma 20mm F1.8 EX DG RF with a length of 90mm, is 40mm shorter. Besides being longer, the Sigma 20mm F1.4 DG HSM A also has a larger diameter of 91mm compared to the Sigma 20mm F1.8 EX DG RF's 89mm 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, 45% (430g) lighter than the Sigma 20mm F1.4 DG HSM A's weight of 950g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Sigma SA Mount for size comparison purposes.
Ultra-Wideangle Lenses in Sigma SA Mount for Size Comparison
Lens Mounts
Both the Sigma 20mm F1.4 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 20mm F1.4 DG HSM A is also available in the Canon EF , Nikon F (FX) and Leica L 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
Both lenses have the same focal range of
20mm but while Sigma 20mm F1.4 DG HSM A has the fastest aperture of
F1.4, the Sigma 20mm F1.8 EX DG RF's widest aperture value is
F1.8.
