The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 16mm F1.4 DC DN X and the Samyang 20mm F1.8 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 16mm F1.4 DC DN X is the longer of the two lenses at 92mm. The Samyang 20mm F1.8 with a length of 88mm is 4mm shorter. On the other hand, the Samyang 20mm F1.8 has a larger diameter of 83mm compared to Sigma 16mm F1.4 DC DN X's 72mm 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. Sigma 16mm F1.4 DC DN X weighs 405g, which means it is 92g (18%) lighter than the Samyang 20mm F1.8 which has a weight of 497g.
Below you can find the dimension and weight table of the 'Wideangle Prime Lenses in Fujifilm X Mount for size comparison purposes.
Wideangle Prime Lenses in Fujifilm X Mount for Size Comparison
Lens Mounts
Both Sigma 16mm F1.4 DC DN X and Samyang 20mm F1.8 has the same Fujifilm X lens mount. Some of the latest released cameras that are compatible with the Fujifilm X lenses are Fujifilm X-T5, Fujifilm X-H2 and Fujifilm X-H2S.
Samyang 20mm F1.8 is also available in Canon EF , Canon EF-M, Micro Four Thirds, Nikon F (FX), Pentax KAF, Samsung NX, Sony Alpha and Sony E mounts.
Focal Range
Sigma 16mm F1.4 DC DN X is a prime lens with fixed focal lenght of 16mm which has an effective (full-frame 35mm equivalent) focal range of 24mm when used on a APS-C / DX format camera. Samyang 20mm F1.8 is a prime lens with fixed focal lenght of 20mm.