The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 14mm F2.8 and the Pentax FA 31mm F1.8 L 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. Samyang 14mm F2.8 is the longer of the two lenses at 96mm. The Pentax FA 31mm F1.8 L with a length of 69mm, is 27mm shorter. Besides being longer, the Samyang 14mm F2.8 also has a larger diameter of 87mm compared to the Pentax FA 31mm F1.8 L's 65mm 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. Pentax FA 31mm F1.8 L weighs 345g, 37% (207g) lighter than the Samyang 14mm F2.8's weight of 552g.
Lens Mounts
Both the Samyang 14mm F2.8 and the Pentax FA 31mm F1.8 L has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Monochrome, Pentax KF and Pentax K-3 III.
Samyang 14mm F2.8 is also available in Canon EF , Nikon F (FX), Four Thirds, Sony Alpha, Sony E and Samsung NX mounts.
Focal Range
Samyang 14mm F2.8 is a prime lens with fixed focal lenght of 14mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
21mm.
On the other hand, the Pentax FA 31mm F1.8 L is a prime lens with fixed focal lenght of 31mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 46.5mm.