The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 20mm F1.8 G and the Carl Zeiss Touit 2.8/12 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 Touit 2.8/12 is the longer of the two lenses at 86mm. The Sony FE 20mm F1.8 G with a length of 85mm, is 1mm shorter. Besides being longer, the Carl Zeiss Touit 2.8/12 also has a larger diameter of 82mm compared to the Sony FE 20mm F1.8 G's 74mm 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. Carl Zeiss Touit 2.8/12 weighs 270g, 27% (103g) lighter than the Sony FE 20mm F1.8 G's weight of 373g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Sony E Mount for size comparison purposes.
Ultra-Wideangle Lenses in Sony E Mount for Size Comparison
Filter Threads
Both the Sony FE 20mm F1.8 G and the Carl Zeiss Touit 2.8/12 have the same Filter thread size of 67mm.
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sony FE 20mm F1.8 G and the Carl Zeiss Touit 2.8/12 has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony FX5, Sony A7R VI and Sony A7 V.
Carl Zeiss Touit 2.8/12 is also available in Fujifilm X mount.
Focal Range
Sony FE 20mm F1.8 G is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
30mm.
On the other hand, the Carl Zeiss Touit 2.8/12 is a prime lens with fixed focal lenght of 12mm which has an effective (full-frame 35mm equivalent) focal range of 18mm when used on a APS-C / DX format camera.