The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Voigtlander 20mm F3.5 SL II and the Zeiss Milvus 18mm F2.8 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. 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 the Voigtlander 20mm F3.5 SL II'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. Voigtlander 20mm F3.5 SL II weighs 205g, which means it is 516g (71%) lighter than the Zeiss Milvus 18mm F2.8 which has a 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.
Ultra-Wideangle Lenses in Nikon F (FX) Mount for Size Comparison
Filter Threads
The Voigtlander 20mm F3.5 SL II has a filter size of 52mm whereas the Zeiss Milvus 18mm F2.8 has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 52mm filters that we recommend you to consider for the Voigtlander 20mm F3.5 SL II:
And these are the 77mm filters that we recommend for the Zeiss Milvus 18mm F2.8:
Lens Mounts
Both the Voigtlander 20mm F3.5 SL II and the Zeiss Milvus 18mm F2.8 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.
Voigtlander 20mm F3.5 SL II is also available in Canon EF and Pentax KAF mounts.
Zeiss Milvus 18mm F2.8 is also available in Canon EF mount.
Focal Range
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 a 35mm (FF) equivalent of
30mm.
On the other hand, the 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 a 35mm (FF) equivalent of 27mm.