The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica Summarit-M 35mm f2.5 and the Carl Zeiss Biogon T2,8/28 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 Biogon T2,8/28 ZM is the longer of the two lenses at 62mm. The Leica Summarit-M 35mm f2.5 with a length of 34mm, is 28mm shorter. Besides being longer, the Carl Zeiss Biogon T2,8/28 ZM also has a larger diameter of 53mm compared to the Leica Summarit-M 35mm f2.5's 51mm 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. Leica Summarit-M 35mm f2.5 weighs 220g, which means it is 10g (4%) lighter than the Carl Zeiss Biogon T2,8/28 ZM which has a weight of 230g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Leica M Mount for size comparison purposes.
Wideangle Lenses in Leica M Mount for Size Comparison
Filter Threads
The Leica Summarit-M 35mm f2.5 has a filter size of 39mm whereas the Carl Zeiss Biogon T2,8/28 ZM has a 46mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 39mm filters that we recommend you to consider for the Leica Summarit-M 35mm f2.5:
And these are the 46mm filters that we recommend for the Carl Zeiss Biogon T2,8/28 ZM:
Lens Mounts
Both the Leica Summarit-M 35mm f2.5 and the Carl Zeiss Biogon T2,8/28 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 Summarit-M 35mm f2.5 is a prime lens with fixed focal lenght of 25-35mm.
On the other hand, the Carl Zeiss Biogon T2,8/28 ZM is a prime lens with fixed focal lenght of 28mm.