The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Rokinon 35mm f1.4 and the Nikon 20mm f2.8D for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Rokinon 35mm f1.4 is the longer of the two lenses at 112mm. The Nikon 20mm f2.8D with a length of 43mm is 69mm shorter. On the other hand, the Nikon 20mm f2.8D has a larger diameter of 69mm compared to Rokinon 35mm f1.4's 63mm 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 f2.8D weighs 270g, 59% (390g) lighter than the Rokinon 35mm f1.4's weight of 660g.
Below you can find the dimension and weight table of the 'Wideangle Prime Lenses in Nikon F (FX) Mount for size comparison purposes.
Wideangle Prime Lenses in Nikon F (FX) Mount for Size Comparison
Lens Mounts
Both Rokinon 35mm f1.4 and Nikon 20mm f2.8D has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Rokinon 35mm f1.4 is also available in Canon EF , Four Thirds, Pentax KAF, Sony Alpha and Samsung NX mounts.
Focal Range
Rokinon 35mm f1.4 is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 52.5mm.
Nikon 20mm f2.8D is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 30mm.