The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Nikon 20mm f1.8G ED and the Rokinon T-S 24mm f3.5 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 T-S 24mm f3.5 is the longer of the two lenses at 112mm. The Nikon 20mm f1.8G ED with a length of 81mm, is 31mm shorter. Besides being longer, the Rokinon T-S 24mm f3.5 also has a larger diameter of 86mm compared to the Nikon 20mm f1.8G ED's 83mm 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. Nikon 20mm f1.8G ED weighs 355g, which means it is 325g (47%) lighter than the Rokinon T-S 24mm f3.5 which has a weight of 680g.
Filter Threads
The Nikon 20mm f1.8G ED has a filter size of 77mm whereas the Rokinon T-S 24mm f3.5 has a 82mm 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 Nikon 20mm f1.8G ED:
And these are the 82mm filters that we recommend for the Rokinon T-S 24mm f3.5:
Lens Mounts
The Nikon 20mm f1.8G ED has the Nikon F (DX) lens mount whereas the Rokinon T-S 24mm f3.5 has the Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (DX) Mount and Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount.
Rokinon T-S 24mm f3.5 is also available in Canon EF and Sony Alpha mounts.
Focal Range
Nikon 20mm f1.8G ED is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
30mm.
On the other hand, the Rokinon T-S 24mm f3.5 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.