The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 20mm F1.8 and the Samyang 16mm f2.0 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 16mm f2.0 is the longer of the two lenses at 89mm. The Samyang 20mm F1.8 with a length of 88mm, is 1mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 83mm.
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. Samyang 20mm F1.8 weighs 497g, which means it is 86g (14%) lighter than the Samyang 16mm f2.0 which has a weight of 583g.
Filter Threads
Both the Samyang 20mm F1.8 and the Samyang 16mm f2.0 have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Samyang 20mm F1.8 and the Samyang 16mm f2.0 has the same Pentax KAF lens mount. Some of the latest released cameras that are compatible with the Pentax KAF lenses are Pentax K-3 III Monochrome, Pentax KF and Pentax K-3 III.
Samyang 20mm F1.8 is also available in Canon EF , Canon EF-M, Fujifilm X, Micro Four Thirds, Nikon F (FX), Samsung NX, Sony Alpha and Sony E mounts.
Samyang 16mm f2.0 is also available in Canon EF , Canon EF-M, Fujifilm X, Nikon F (DX), Four Thirds, Micro Four Thirds, Sony Alpha, Sony E and Samsung NX mounts.
Focal Range
Samyang 20mm F1.8 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 Samyang 16mm f2.0 is a prime lens with fixed focal lenght of 16mm which has an effective (full-frame 35mm equivalent) focal range of 24mm when used on a APS-C / DX format camera.