The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Nikon 20mm f1.8G ED and the Sigma 20mm F1.8 EX DG RF for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sigma 20mm F1.8 EX DG RF is the longer of the two lenses at 90mm. The Nikon 20mm f1.8G ED with a length of 81mm is 9mm shorter. Besides being longer, the Sigma 20mm F1.8 EX DG RF also has a larger diameter of 89mm compared to Nikon 20mm f1.8G ED's 83mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Nikon 20mm f1.8G ED weighs 355g, which means it is 165g (31%) lighter than the Sigma 20mm F1.8 EX DG RF which has a weight of 520g.
Below you can find the dimension and weight table of the 'Wideangle Prime Lenses in Nikon F (DX) Mount for size comparison purposes.
Wideangle Prime Lenses in Nikon F (DX) Mount for Size Comparison
Both Nikon 20mm f1.8G ED and Sigma 20mm F1.8 EX DG RF has the same Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (DX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Sigma 20mm F1.8 EX DG RF is also available in Canon EF , Pentax KAF, Sony Alpha and Sigma SA mounts.
Both lenses have the same focal range of 20mm and the fastest aperture of F1.8.