The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 35mm F1.8 and the ZEISS Loxia 21mm F2.8 for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Sony FE 35mm F1.8 is the longer of the two lenses at 73mm. The ZEISS Loxia 21mm F2.8 with a length of 72mm, is 1mm shorter. Besides being longer, the Sony FE 35mm F1.8 also has a larger diameter of 66mm compared to the ZEISS Loxia 21mm F2.8's 62mm diameter.
The 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. Sony FE 35mm F1.8 weighs 280g, which means it is 114g (28%) lighter than the ZEISS Loxia 21mm F2.8 which has a weight of 394g.
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 the Sony FE 35mm F1.8 and the 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 ZV-E1, Sony A7R V and Sony FX30.
Sony FE 35mm F1.8 is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 52.5mm.
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 a 35mm (FF) equivalent of 31.5mm.