The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Leica APO 135mm f3.4 ASPH and the Leica APO 75mm f2 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 APO 135mm f3.4 ASPH is the longer of the two lenses at 105mm. The Leica APO 75mm f2 ASPH with a length of 67mm, is 38mm shorter. Besides being longer, the Leica APO 135mm f3.4 ASPH also has a larger diameter of 59mm compared to the Leica APO 75mm f2 ASPH's 58mm 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 APO 75mm f2 ASPH weighs 430g, 4% (20g) lighter than the Leica APO 135mm f3.4 ASPH's weight of 450g.
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
Both the Leica APO 135mm f3.4 ASPH and the Leica APO 75mm f2 ASPH have the same Filter thread size of 49mm.
Below are links to the 49mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Leica APO 135mm f3.4 ASPH and the Leica APO 75mm f2 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 APO 135mm f3.4 ASPH is a prime lens with fixed focal lenght of 135mm.
On the other hand, the Leica APO 75mm f2 ASPH is a prime lens with fixed focal lenght of 75mm.