The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Venus 100mm F2.8 2X Ultra Macro and the Rokinon 85mm F1.8 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. Venus 100mm F2.8 2X Ultra Macro is the longer of the two lenses at 125mm. The Rokinon 85mm F1.8 with a length of 81mm, is 44mm shorter. Besides being longer, the Venus 100mm F2.8 2X Ultra Macro also has a larger diameter of 72mm compared to the Rokinon 85mm F1.8's 68mm 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 F1.8 weighs 344g, 46% (294g) lighter than the Venus 100mm F2.8 2X Ultra Macro's weight of 638g.
Filter Threads
The Venus 100mm F2.8 2X Ultra Macro has a filter size of 67mm whereas the Rokinon 85mm F1.8 has a 62mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Venus 100mm F2.8 2X Ultra Macro:
And these are the 62mm filters that we recommend for the Rokinon 85mm F1.8:
Lens Mounts
Both the Venus 100mm F2.8 2X Ultra Macro and the Rokinon 85mm F1.8 has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A9 III, Sony A7C Mark II and Sony A7CR.
Venus 100mm F2.8 2X Ultra Macro is also available in Canon EF , Nikon F (FX) and Pentax KAF2 mounts.
Rokinon 85mm F1.8 is also available in Canon EF-M and Fujifilm X mounts.
Focal Range
Venus 100mm F2.8 2X Ultra Macro is a prime lens with fixed focal lenght of 100mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
150mm.
On the other hand, the Rokinon 85mm F1.8 is a prime lens with fixed focal lenght of 85mm which has an effective (full-frame 35mm equivalent) focal range of 127.5mm when used on a APS-C / DX format camera.