The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica Elmarit-M 21mm f2.8 ASPH and the Carl Zeiss C Biogon T2,8/35 ZM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Carl Zeiss C Biogon T2,8/35 ZM is the longer of the two lenses at 55mm. The Leica Elmarit-M 21mm f2.8 ASPH with a length of 46mm, is 9mm shorter. On the other hand, the Leica Elmarit-M 21mm f2.8 ASPH has a larger diameter of 58mm compared to the Carl Zeiss C Biogon T2,8/35 ZM's 52mm diameter.
The 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. Carl Zeiss C Biogon T2,8/35 ZM weighs 200g, 33% (100g) lighter than the Leica Elmarit-M 21mm f2.8 ASPH's weight of 300g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Leica M Mount for size comparison purposes.
Wideangle Prime Lenses in Leica M Mount for Size Comparison
Lens Mounts
Both the Leica Elmarit-M 21mm f2.8 ASPH and the Carl Zeiss C Biogon T2,8/35 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 Elmarit-M 21mm f2.8 ASPH is a prime lens with fixed focal lenght of 21mm. Carl Zeiss C Biogon T2,8/35 ZM is a prime lens with fixed focal lenght of 35mm.