The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica Summilux-M 21mm f1.4 Asph and the Carl Zeiss Distagon T4/18 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 Distagon T4/18 ZM is the longer of the two lenses at 71mm. The Leica Summilux-M 21mm f1.4 Asph with a length of 66mm, is 5mm shorter. On the other hand, the Leica Summilux-M 21mm f1.4 Asph has a larger diameter of 70mm compared to the Carl Zeiss Distagon T4/18 ZM's 65mm 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. Carl Zeiss Distagon T4/18 ZM weighs 350g, 39% (230g) lighter than the Leica Summilux-M 21mm f1.4 Asph's weight of 580g.
Lens Mounts
Both the Leica Summilux-M 21mm f1.4 Asph and the Carl Zeiss Distagon T4/18 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 Summilux-M 21mm f1.4 Asph is a prime lens with fixed focal lenght of 21mm.
On the other hand, the Carl Zeiss Distagon T4/18 ZM is a prime lens with fixed focal lenght of 18mm.