The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica Super-Elmar-M 21mm f3.4 ASPH and the Carl Zeiss Biogon T2,8/28 ZM 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. Carl Zeiss Biogon T2,8/28 ZM is the longer of the two lenses at 62mm. The Leica Super-Elmar-M 21mm f3.4 ASPH with a length of 43mm, is 19mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 53mm.
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. Carl Zeiss Biogon T2,8/28 ZM weighs 230g, 17% (49g) lighter than the Leica Super-Elmar-M 21mm f3.4 ASPH's weight of 279g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Leica M Mount for size comparison purposes.
Wideangle Lenses in Leica M Mount for Size Comparison
Filter Threads
Both the Leica Super-Elmar-M 21mm f3.4 ASPH and the Carl Zeiss Biogon T2,8/28 ZM have the same Filter thread size of 46mm.
Below are links to the 46mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Leica Super-Elmar-M 21mm f3.4 ASPH and the Carl Zeiss Biogon T2,8/28 ZM 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
Leica Super-Elmar-M 21mm f3.4 ASPH is a prime lens with fixed focal lenght of 21mm.
On the other hand, the Carl Zeiss Biogon T2,8/28 ZM is a prime lens with fixed focal lenght of 28mm.