The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Rokinon 14mm f2.8 and the Pentax 15mm F4 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. Rokinon 14mm f2.8 is the longer of the two lenses at 96mm. The Pentax 15mm F4 L with a length of 40mm, is 56mm shorter. Besides being longer, the Rokinon 14mm f2.8 also has a larger diameter of 87mm compared to the Pentax 15mm F4 L's 63mm 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 15mm F4 L weighs 212g, 61% (340g) lighter than the Rokinon 14mm f2.8's weight of 552g.
Lens Mounts
Both the Rokinon 14mm f2.8 and the Pentax 15mm F4 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 Mono, Pentax KF and Pentax K-3 III.
Rokinon 14mm f2.8 is also available in the Canon EF , Nikon F (FX), Four Thirds, Sony Alpha and Samsung NX mounts.
Focal Range
Rokinon 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 15mm F4 L is a prime lens with fixed focal lenght of 15mm which has an effective (full-frame 35mm equivalent) focal range of 22.5mm when used on a APS-C / DX format camera.
