The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica APO 50mm f2 ASPH 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 APO 50mm f2 ASPH with a length of 47mm, is 21mm shorter. On the other hand, the Leica APO 50mm f2 ASPH 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, 23% (70g) lighter than the Leica APO 50mm f2 ASPH's weight of 300g.
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 APO 50mm f2 ASPH 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.