The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica Summicron-M 50mm f2 and the Carl Zeiss Planar T2/50 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 Planar T2/50 ZM is the longer of the two lenses at 68mm. The Leica Summicron-M 50mm f2 with a length of 44mm, is 24mm shorter. On the other hand, the Leica Summicron-M 50mm f2 has a larger diameter of 53mm compared to the Carl Zeiss Planar T2/50 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 Planar T2/50 ZM weighs 230g, 4% (10g) lighter than the Leica Summicron-M 50mm f2's weight of 240g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Leica M Mount for size comparison purposes.
Standard Prime Lenses in Leica M Mount for Size Comparison
Both the Leica Summicron-M 50mm f2 and the Carl Zeiss Planar T2/50 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.
Both lenses have the same focal range of 50mm and the fastest aperture of F2.0.