The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Voigtlander 12mm F5.6 and the Leica Super-Elmar-M 21mm f3.4 ASPH for their suitability to various photography scenarios:
Size and Weight Comparison
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 12mm F5.6 weighs 230g, which means it is 49g (17%) lighter than the Leica Super-Elmar-M 21mm f3.4 ASPH which has a weight of 279g.
Filter Threads
The Voigtlander 12mm F5.6 has a filter size of 67mm whereas the Leica Super-Elmar-M 21mm f3.4 ASPH has a 46mm 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 Voigtlander 12mm F5.6:
And these are the 46mm filters that we recommend for the Leica Super-Elmar-M 21mm f3.4 ASPH:
Lens Mounts
Both the Voigtlander 12mm F5.6 and the Leica Super-Elmar-M 21mm f3.4 ASPH has the same Leica M lens mount. Some of the latest released cameras that are compatible with the Leica M lenses are Leica M11 Monochrome, Leica M11 and Leica M10.
Focal Range
Voigtlander 12mm F5.6 is a prime lens with fixed focal lenght of 12mm.
On the other hand, the Leica Super-Elmar-M 21mm f3.4 ASPH is a prime lens with fixed focal lenght of 21mm.