The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang AF 18mm F2.8 FE and the Samyang 12mm f2.0 for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Samyang AF 18mm F2.8 FE is the longer of the two lenses at 61mm. The Samyang 12mm f2.0 with a length of 59mm, is 2mm shorter. On the other hand, the Samyang 12mm f2.0 has a larger diameter of 73mm compared to the Samyang AF 18mm F2.8 FE's 64mm diameter.
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. Samyang AF 18mm F2.8 FE weighs 145g, which means it is 115g (44%) lighter than the Samyang 12mm f2.0 which has a weight of 260g.
The Samyang AF 18mm F2.8 FE has the Sony E lens mount whereas the Samyang 12mm f2.0 has the Canon EF-M lens mount. Some of the latest released cameras that are compatible with these mounts are Sony ZV-E1, Sony A7R V and Sony FX30 for the Sony E Mount and , and for the Canon EF-M Mount.
Samyang 12mm f2.0 is also available in Fujifilm X , Micro Four Thirds, Sony E and Samsung NX mounts.
Samyang AF 18mm F2.8 FE is a prime lens with fixed focal lenght of 18mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 27mm.
Samyang 12mm f2.0 is a prime lens with fixed focal lenght of 12mm which has an effective (full-frame 35mm equivalent) focal range of 18mm when used on a APS-C / DX format camera.