The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang AF 14mm F2.8 and the Carl Zeiss Touit 2.8/12 for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Samyang AF 14mm F2.8 is the longer of the two lenses at 98mm. The Carl Zeiss Touit 2.8/12 with a length of 86mm is 12mm shorter. Besides being longer, the Samyang AF 14mm F2.8 also has a larger diameter of 86mm compared to Carl Zeiss Touit 2.8/12's 82mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Carl Zeiss Touit 2.8/12 weighs 270g, 46% (235g) lighter than the Samyang AF 14mm F2.8's weight of 505g.
Below you can find the dimension and weight table of the 'Wideangle Prime Lenses in Sony E Mount for size comparison purposes.
Wideangle Prime Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both Samyang AF 14mm F2.8 and 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 A7R V, Sony FX30 and Sony A7 IV.
Carl Zeiss Touit 2.8/12 is also available in Fujifilm X mount.
Focal Range
Samyang AF 14mm F2.8 is a prime lens with fixed focal lenght of 14mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 21mm.
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.