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 Voigtlander Nokton 17.5mm F0.95 ASPH 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 20mm F1.8 is the longer of the two lenses at 88mm. The Voigtlander Nokton 17.5mm F0.95 ASPH with a length of 80mm, is 8mm shorter. Besides being longer, the Samyang 20mm F1.8 also has a larger diameter of 83mm compared to the Voigtlander Nokton 17.5mm F0.95 ASPH'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. Samyang 20mm F1.8 weighs 497g, which means it is 43g (7%) lighter than the Voigtlander Nokton 17.5mm F0.95 ASPH which has a weight of 540g.
Filter Threads
The Samyang 20mm F1.8 has a filter size of 77mm whereas the Voigtlander Nokton 17.5mm F0.95 ASPH has a 58mm 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 Samyang 20mm F1.8:
And these are the 58mm filters that we recommend for the Voigtlander Nokton 17.5mm F0.95 ASPH:
Lens Mounts
Both the Samyang 20mm F1.8 and the Voigtlander Nokton 17.5mm F0.95 ASPH has the same Micro Four Thirds lens mount. Some of the latest released cameras that are compatible with the Micro Four Thirds lenses are OM System OM-1 II, Panasonic G9 II and OM System OM-5.
Samyang 20mm F1.8 is also available in Canon EF , Canon EF-M, Fujifilm X, Nikon F (FX), Pentax KAF, Samsung NX, Sony Alpha and Sony E mounts.
Focal Range
Samyang 20mm F1.8 is a prime lens with fixed focal lenght of 20mm.
On the other hand, the Voigtlander Nokton 17.5mm F0.95 ASPH is a prime lens with fixed focal lenght of 18mm which has an effective (full-frame 35mm equivalent) focal range of 36mm when used on a FourThirds format camera.