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 Samyang 8mm F3.5 Fisheye 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. Nikon 20mm f1.8G ED is the longer of the two lenses at 81mm. The Samyang 8mm F3.5 Fisheye with a length of 77mm, is 4mm shorter. Besides being longer, the Nikon 20mm f1.8G ED also has a larger diameter of 83mm compared to the Samyang 8mm F3.5 Fisheye's 75mm 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 88g (19%) lighter than the Samyang 8mm F3.5 Fisheye which has a weight of 443g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Nikon F (DX) Mount for size comparison purposes.
Ultra-Wideangle Lenses in Nikon F (DX) Mount for Size Comparison
Lens Mounts
Both the Nikon 20mm f1.8G ED and the Samyang 8mm F3.5 Fisheye has the same Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (DX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Samyang 8mm F3.5 Fisheye is also available in Canon EF , Four Thirds, Pentax KAF, Sony Alpha and Samsung NX 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 Samyang 8mm F3.5 Fisheye is a prime lens with fixed focal lenght of 8mm which has an effective (full-frame 35mm equivalent) focal range of 12mm when used on a APS-C / DX format camera.
