The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 105mm F1.4 DG HSM 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. Sigma 105mm F1.4 DG HSM is the longer of the two lenses at 132mm. The Rokinon 85mm F1.4 with a length of 75mm, is 57mm shorter. Besides being longer, the Sigma 105mm F1.4 DG HSM also has a larger diameter of 116mm 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, 67% (1106g) lighter than the Sigma 105mm F1.4 DG HSM's weight of 1645g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Nikon F (FX) Mount for size comparison purposes.
Telephoto Lenses in Nikon F (FX) Mount for Size Comparison
Filter Threads
The Sigma 105mm F1.4 DG HSM has a filter size of 105mm 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 105mm filters that we recommend you to consider for the Sigma 105mm F1.4 DG HSM:
And these are the 72mm filters that we recommend for the Rokinon 85mm F1.4:
Lens Mounts
Both the Sigma 105mm F1.4 DG HSM and the Rokinon 85mm F1.4 has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Sigma 105mm F1.4 DG HSM is also available in Canon EF , Sigma SA and Sony E mounts.
Rokinon 85mm F1.4 is also available in Canon EF , Four Thirds, Pentax KAF, Sony Alpha and Samsung NX mounts.
Focal Range
Sigma 105mm F1.4 DG HSM is a prime lens with fixed focal lenght of 105mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
157.5mm.
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.