The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 24mm F2.8 STM and the Rokinon 24mm f1.4 for their suitability to various photography scenarios:
Size and Weight Comparison
The 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. Canon 24mm F2.8 STM weighs 125g, which means it is 455g (78%) lighter than the Rokinon 24mm f1.4 which has a weight of 580g.
The Canon 24mm F2.8 STM has the Canon EF-S lens mount whereas the Rokinon 24mm f1.4 has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount and Canon 1D X III, Canon 6D MII and Canon 5D MIV for the Canon EF Mount.
Rokinon 24mm f1.4 is also available in Nikon F (FX) , Four Thirds, Pentax KAF, Sony Alpha and Samsung NX mounts.
Both lenses have the same focal range of 24mm but while Canon 24mm F2.8 STM has the fastest aperture of F2.8, the Rokinon 24mm f1.4's widest aperture value is F1.4.