The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Zeiss Milvus 18mm F2.8 and the Voigtlander 20mm F3.5 SL II for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Zeiss Milvus 18mm F2.8 is the longer of the two lenses at 93mm. The Voigtlander 20mm F3.5 SL II with a length of 29mm is 64mm shorter. Besides being longer, the Zeiss Milvus 18mm F2.8 also has a larger diameter of 73mm compared to Voigtlander 20mm F3.5 SL II's 63mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Voigtlander 20mm F3.5 SL II weighs 205g, 71% (516g) lighter than the Zeiss Milvus 18mm F2.8's weight of 721g.
Below you can find the dimension and weight table of the 'Wideangle Prime Lenses in Nikon F (FX) Mount for size comparison purposes.
Wideangle Prime Lenses in Nikon F (FX) Mount for Size Comparison
Lens Mounts
Both Zeiss Milvus 18mm F2.8 and Voigtlander 20mm F3.5 SL II has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Zeiss Milvus 18mm F2.8 is also available in Canon EF mount.
Voigtlander 20mm F3.5 SL II is also available in Canon EF and Pentax KAF mounts.
Focal Range
Zeiss Milvus 18mm F2.8 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 an 35mm (FF) equivalent of 27mm.
Voigtlander 20mm F3.5 SL II 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 an 35mm (FF) equivalent of 30mm.