The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 28mm 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 28mm F1.4 DG HSM A is the longer of the two lenses at 108mm. The Sigma 20mm F1.8 EX DG RF with a length of 90mm, is 18mm shorter. On the other hand, the Sigma 20mm F1.8 EX DG RF has a larger diameter of 89mm compared to the Sigma 28mm F1.4 DG HSM A's 83mm 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, 39% (345g) lighter than the Sigma 28mm F1.4 DG HSM A's weight of 865g.
Filter Threads
The Sigma 28mm F1.4 DG HSM A has a filter size of 77mm whereas the Sigma 20mm F1.8 EX DG RF has a 82mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Sigma 28mm F1.4 DG HSM A:
And these are the 82mm filters that we recommend for the Sigma 20mm F1.8 EX DG RF:
Lens Mounts
Both the Sigma 28mm 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 28mm F1.4 DG HSM A is also available in the Canon EF , Nikon F (FX), Sony E 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
Sigma 28mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 28mm.
On the other hand, the Sigma 20mm F1.8 EX DG RF is a prime lens with fixed focal lenght of 20mm.
