The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica Summarit-M 75mm F2.4 ASPH and the Carl Zeiss Sonnar T2/85 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 Sonnar T2/85 ZM is the longer of the two lenses at 100mm. The Leica Summarit-M 75mm F2.4 ASPH with a length of 61mm, is 39mm shorter. Besides being longer, the Carl Zeiss Sonnar T2/85 ZM also has a larger diameter of 70mm compared to the Leica Summarit-M 75mm F2.4 ASPH's 55mm 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. Leica Summarit-M 75mm F2.4 ASPH weighs 325g, which means it is 175g (35%) lighter than the Carl Zeiss Sonnar T2/85 ZM which has a weight of 500g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Leica M Mount for size comparison purposes.
Telephoto Prime Lenses in Leica M Mount for Size Comparison
Lens Mounts
Both the Leica Summarit-M 75mm F2.4 ASPH and the Carl Zeiss Sonnar T2/85 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, Leica M10 and Leica M Typ 262.
Focal Range
Leica Summarit-M 75mm F2.4 ASPH is a prime lens with fixed focal lenght of 75mm. Carl Zeiss Sonnar T2/85 ZM is a prime lens with fixed focal lenght of 85mm.