The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica Thambar-M 90mm F2.2 and the Leica Summarit-M 75mm F2.4 ASPH 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. Leica Thambar-M 90mm F2.2 is the longer of the two lenses at 90mm. The Leica Summarit-M 75mm F2.4 ASPH with a length of 61mm, is 29mm shorter. Besides being longer, the Leica Thambar-M 90mm F2.2 also has a larger diameter of 57mm compared to the Leica Summarit-M 75mm F2.4 ASPH's 55mm 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 75mm F2.4 ASPH weighs 325g, 35% (175g) lighter than the Leica Thambar-M 90mm F2.2's 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 Lenses in Leica M Mount for Size Comparison
Filter Threads
The Leica Thambar-M 90mm F2.2 has a filter size of 49mm whereas the Leica Summarit-M 75mm F2.4 ASPH 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 49mm filters that we recommend you to consider for the Leica Thambar-M 90mm F2.2:
And these are the 46mm filters that we recommend for the Leica Summarit-M 75mm F2.4 ASPH:
Lens Mounts
Both the Leica Thambar-M 90mm F2.2 and the Leica Summarit-M 75mm F2.4 ASPH 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 Thambar-M 90mm F2.2 is a prime lens with fixed focal lenght of 90mm.
On the other hand, the Leica Summarit-M 75mm F2.4 ASPH is a prime lens with fixed focal lenght of 75mm.