Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Canon RF 85mm F1.2L USM is the longer of the two lenses at 117mm. The Samyang MF 85mm F1.4 RF with a length of 99mm is 18mm shorter. Besides being longer, the Canon RF 85mm F1.2L USM also has a larger diameter of 103mm compared to Samyang MF 85mm F1.4 RF's 78mm diameter.
Below you can find the scaled side by side image of Samyang MF 85mm F1.4 RF and Canon RF 85mm F1.2L USM to get a better idea of how their size compare in real life.
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. Samyang MF 85mm F1.4 RF weighs 730g, which means it is 465g (63%) lighter than the Canon RF 85mm F1.2L USM which has a weight of 1195g.
Below you can find the dimension and weight table of the 'Telephoto Prime Lenses in Canon RF Mount for size comparison purposes.
Telephoto Prime Lenses in Canon RF Mount for Size Comparison
Both Samyang MF 85mm F1.4 RF and Canon RF 85mm F1.2L USM has the same Canon RF lens mount. Some of the latest released cameras that are compatible with the Canon RF lenses are Canon R10, Canon R7 and Canon R5 C.