The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 20mm F1.8 G and the Voigtlander 21mm F1.8 Ultron 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. Voigtlander 21mm F1.8 Ultron is the longer of the two lenses at 92mm. The Sony FE 20mm F1.8 G with a length of 85mm, is 7mm shorter. On the other hand, the Sony FE 20mm F1.8 G has a larger diameter of 74mm compared to the Voigtlander 21mm F1.8 Ultron's 62mm 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. Sony FE 20mm F1.8 G weighs 373g, which means it is 39g (9%) lighter than the Voigtlander 21mm F1.8 Ultron which has a weight of 412g.
Filter Threads
The Sony FE 20mm F1.8 G has a filter size of 67mm whereas the Voigtlander 21mm F1.8 Ultron 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 67mm filters that we recommend you to consider for the Sony FE 20mm F1.8 G:
And these are the 58mm filters that we recommend for the Voigtlander 21mm F1.8 Ultron:
Lens Mounts
The Sony FE 20mm F1.8 G has the Sony E lens mount whereas the Voigtlander 21mm F1.8 Ultron has the Leica M lens mount. Some of the latest released cameras that are compatible with these mounts are Sony A9 III, Sony A7C Mark II and Sony A7CR for the Sony E Mount and Leica M11 Monochrome, Leica M11 and Leica M10 for the Leica M Mount.
Focal Range
Sony FE 20mm F1.8 G 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 Voigtlander 21mm F1.8 Ultron is a prime lens with fixed focal lenght of 21mm.