The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Rokinon 24mm f1.4 and the Pentax 15mm F4 ED AL L for their suitability to various photography scenarios:
Size and Weight Comparison
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 ED AL L weighs 189g, 67% (391g) lighter than the Rokinon 24mm f1.4's weight of 580g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Pentax KAF Mount for size comparison purposes.
Wideangle Lenses in Pentax KAF Mount for Size Comparison
Filter Threads
The Rokinon 24mm f1.4 has a filter size of 77mm whereas the Pentax 15mm F4 ED AL L has a 49mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Rokinon 24mm f1.4:
And these are the 49mm filters that we recommend for the Pentax 15mm F4 ED AL L:
Lens Mounts
Both the Rokinon 24mm f1.4 and the Pentax 15mm F4 ED AL 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 24mm f1.4 is also available in the Canon EF , Nikon F (FX), Four Thirds, Sony Alpha and Samsung NX mounts.
Focal Range
Rokinon 24mm f1.4 is a prime lens with fixed focal lenght of 24mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
36mm.
On the other hand, the Pentax 15mm F4 ED AL 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.
