The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica APO 90mm f2 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 APO 90mm f2 ASPH with a length of 78mm, is 22mm shorter. Besides being longer, the Carl Zeiss Sonnar T2/85 ZM also has a larger diameter of 70mm compared to the Leica APO 90mm f2 ASPH's 64mm 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.
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
Both the Leica APO 90mm f2 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 Monochrome, Leica M11 and Leica M10.
Leica APO 90mm f2 ASPH is a prime lens with fixed focal lenght of 90mm. Carl Zeiss Sonnar T2/85 ZM is a prime lens with fixed focal lenght of 85mm.