The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Irix 11mm F4 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. Irix 11mm F4 is the longer of the two lenses at 118mm. The Samyang 12mm f2.0 with a length of 59mm, is 59mm shorter. Besides being longer, the Irix 11mm F4 also has a larger diameter of 103mm compared to the Samyang 12mm f2.0's 73mm 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 12mm f2.0 weighs 260g, 67% (530g) lighter than the Irix 11mm F4's weight of 790g.
The Irix 11mm F4 has the Canon EF 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 Canon 1D X III, Canon 6D MII and Canon 5D MIV for the Canon EF Mount and , and for the Canon EF-M Mount.
Irix 11mm F4 is also available in Nikon F (FX) and Pentax KAF3 mounts.
Samyang 12mm f2.0 is also available in Fujifilm X , Micro Four Thirds, Sony E and Samsung NX mounts.
Irix 11mm F4 is a prime lens with fixed focal lenght of 11mm. 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.