The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Pentax D FA 70-200mm F2.8ED and the Rokinon 85mm F1.4 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. Pentax D FA 70-200mm F2.8ED is the longer of the two lenses at 203mm. The Rokinon 85mm F1.4 with a length of 75mm, is 128mm shorter. Besides being longer, the Pentax D FA 70-200mm F2.8ED also has a larger diameter of 92mm compared to the Rokinon 85mm F1.4's 78mm 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. Rokinon 85mm F1.4 weighs 539g, 69% (1216g) lighter than the Pentax D FA 70-200mm F2.8ED's weight of 1755g.
Filter Threads
The Pentax D FA 70-200mm F2.8ED has a filter size of 77mm whereas the Rokinon 85mm F1.4 has a 72mm 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 Pentax D FA 70-200mm F2.8ED:
And these are the 72mm filters that we recommend for the Rokinon 85mm F1.4:
Lens Mounts
The Pentax D FA 70-200mm F2.8ED has the Pentax KAF3 lens mount whereas the Rokinon 85mm F1.4 has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF3 Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Rokinon 85mm F1.4 is also available in Canon EF , Four Thirds, Sony Alpha, Samsung NX and Nikon F (FX) mounts.
Focal Range
Pentax D FA 70-200mm F2.8ED has a focal range of 70-200mm and
2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
105 - 300mm.
On the other hand, the Rokinon 85mm F1.4 is a prime lens with fixed focal lenght of 85mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 127.5mm.
