The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Thypoch 21mm f3.5 and the Voigtlander 28mm f2.8 Type I 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. Thypoch 21mm f3.5 is the longer of the two lenses at 35mm. The Voigtlander 28mm f2.8 Type I with a length of 24mm, is 11mm shorter. Besides being longer, the Thypoch 21mm f3.5 also has a larger diameter of 58mm compared to the Voigtlander 28mm f2.8 Type I's 52mm 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. Thypoch 21mm f3.5 weighs 131g, which means it is 12g (8%) lighter than the Voigtlander 28mm f2.8 Type I which has a weight of 143g.
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 Thypoch 21mm f3.5 has a filter size of 39mm whereas the Voigtlander 28mm f2.8 Type I has a 34mm 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 Thypoch 21mm f3.5:
And these are the 34mm filters that we recommend for the Voigtlander 28mm f2.8 Type I:
Lens Mounts
Both the Thypoch 21mm f3.5 and the Voigtlander 28mm f2.8 Type I has the same Leica M lens mount. Some of the latest released cameras that are compatible with the Leica M lenses are Leica M EV1, Leica M11-D and Pixii Max.
Focal Range
Thypoch 21mm f3.5 is a prime lens with fixed focal lenght of 21mm.
On the other hand, the Voigtlander 28mm f2.8 Type I is a prime lens with fixed focal lenght of 28mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 42mm.
