The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tokina Firin 20mm F2 FE MF and the ZEISS Loxia 21mm F2.8 for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Tokina Firin 20mm F2 FE MF is the longer of the two lenses at 82mm. The ZEISS Loxia 21mm F2.8 with a length of 72mm is 10mm shorter. Besides being longer, the Tokina Firin 20mm F2 FE MF also has a larger diameter of 69mm compared to ZEISS Loxia 21mm F2.8's 62mm 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. ZEISS Loxia 21mm F2.8 weighs 394g, 19% (96g) lighter than the Tokina Firin 20mm F2 FE MF's weight of 490g.
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
Both Tokina Firin 20mm F2 FE MF and ZEISS Loxia 21mm F2.8 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.
Tokina Firin 20mm F2 FE MF is also available in Sony E mount.
Tokina Firin 20mm F2 FE MF 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 an 35mm (FF) equivalent of 30mm.
ZEISS Loxia 21mm F2.8 is a prime lens with fixed focal lenght of 21mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 31.5mm.