Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Rokinon 85mm F1.8 is the longer of the two lenses at 81mm. The Samyang MF 85mm F1.4 Mk2 with a length of 75mm is 6mm shorter. On the other hand, the Samyang MF 85mm F1.4 Mk2 has a larger diameter of 78mm compared to Rokinon 85mm F1.8's 68mm 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. Rokinon 85mm F1.8 weighs 344g, 37% (204g) lighter than the Samyang MF 85mm F1.4 Mk2's weight of 548g.
Below you can find the dimension and weight table of the 'Telephoto Prime Lenses in Fujifilm X Mount for size comparison purposes.
Telephoto Prime Lenses in Fujifilm X Mount for Size Comparison
Both Samyang MF 85mm F1.4 Mk2 and Rokinon 85mm 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-H2, Fujifilm X-H2S and Fujifilm X-T30 II.
Samyang MF 85mm F1.4 Mk2 is also available in Canon EF , Canon EF-M, Micro Four Thirds, Nikon F (FX) and Sony E mounts.
Rokinon 85mm F1.8 is also available in Canon EF-M and Sony E mounts.