The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Nikon PC 19mm F4E ED and the Sigma 20mm F1.8 EX DG RF 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 PC 19mm F4E ED is the longer of the two lenses at 124mm. The Sigma 20mm F1.8 EX DG RF with a length of 90mm, is 34mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 89mm.
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. Sigma 20mm F1.8 EX DG RF weighs 520g, 41% (365g) lighter than the Nikon PC 19mm F4E ED's weight of 885g.
Lens Mounts
The Nikon PC 19mm F4E ED has the Nikon F (FX) lens mount whereas the Sigma 20mm F1.8 EX DG RF has the Nikon F (DX) 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 (FX) Mount and Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (DX) Mount.
Sigma 20mm F1.8 EX DG RF is also available in Canon EF , Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Nikon PC 19mm F4E ED is a prime lens with fixed focal lenght of 19mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
28.5mm.
On the other hand, the Sigma 20mm F1.8 EX DG RF 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.