The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 20mm F1.8 G 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 F1.8 EX DG RF is the longer of the two lenses at 90mm. The Sony FE 20mm F1.8 G with a length of 85mm, is 5mm shorter. Besides being longer, the Sigma 20mm F1.8 EX DG RF also has a larger diameter of 89mm compared to the Sony FE 20mm F1.8 G's 74mm 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. Sony FE 20mm F1.8 G weighs 373g, which means it is 147g (28%) lighter than the Sigma 20mm F1.8 EX DG RF which has a weight of 520g.
Filter Threads
The Sony FE 20mm F1.8 G has a filter size of 67mm 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 67mm filters that we recommend you to consider for the Sony FE 20mm F1.8 G:
And these are the 82mm filters that we recommend for the Sigma 20mm F1.8 EX DG RF:
Lens Mounts
The Sony FE 20mm F1.8 G has the Sony E lens mount whereas the Sigma 20mm F1.8 EX DG RF has the Sigma SA lens mount. Some of the latest released cameras that are compatible with these mounts are Sony A9 III, Sony A7C Mark II and Sony A7CR for the Sony E Mount and Sigma Quattro, Sigma Quattro H and Sigma SD1 Merrill for the Sigma SA Mount.
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 and the fastest aperture of
F1.8.