The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang AF 18mm F2.8 FE and the Sony E 20mm F2.8 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. Samyang AF 18mm F2.8 FE is the longer of the two lenses at 61mm. The Sony E 20mm F2.8 with a length of 20mm, is 41mm shorter. Besides being longer, the Samyang AF 18mm F2.8 FE also has a larger diameter of 64mm compared to the Sony E 20mm F2.8's 63mm 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. Sony E 20mm F2.8 weighs 69g, 52% (76g) lighter than the Samyang AF 18mm F2.8 FE's weight of 145g.
Filter Threads
The Samyang AF 18mm F2.8 FE has a filter size of 58mm whereas the Sony E 20mm F2.8 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 58mm filters that we recommend you to consider for the Samyang AF 18mm F2.8 FE:
And these are the 49mm filters that we recommend for the Sony E 20mm F2.8:
Lens Mounts
Both the Samyang AF 18mm F2.8 FE and the Sony E 20mm F2.8 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.
Focal Range
Samyang AF 18mm F2.8 FE is a prime lens with fixed focal lenght of 18mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
27mm.
On the other hand, the Sony E 20mm F2.8 is a prime lens with fixed focal lenght of 20mm which has an effective (full-frame 35mm equivalent) focal range of 30mm when used on a APS-C / DX format camera.