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 8mm F3.5 Fisheye for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Irix 11mm F4 is the longer of the two lenses at 118mm. The Samyang 8mm F3.5 Fisheye with a length of 77mm, is 41mm shorter. Besides being longer, the Irix 11mm F4 also has a larger diameter of 103mm compared to the Samyang 8mm F3.5 Fisheye's 75mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Samyang 8mm F3.5 Fisheye weighs 443g, 43% (347g) lighter than the Irix 11mm F4's weight of 790g.
Lens Mounts
The Irix 11mm F4 has the Nikon F (FX) lens mount whereas the Samyang 8mm F3.5 Fisheye has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Irix 11mm F4 is also available in the Canon EF and Pentax KAF3 mounts.
Samyang 8mm F3.5 Fisheye is also available in Canon EF , Nikon F (DX), Four Thirds, Sony Alpha and Samsung NX mounts.
Focal Range
Irix 11mm F4 is a prime lens with fixed focal lenght of 11mm.
On the other hand, the Samyang 8mm F3.5 Fisheye is a prime lens with fixed focal lenght of 8mm which has an effective (full-frame 35mm equivalent) focal range of 12mm when used on a APS-C / DX format camera.
