The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 24-240mm F3.5-6.3 OSS and the ZEISS Loxia 21mm F2.8 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. Sony FE 24-240mm F3.5-6.3 OSS is the longer of the two lenses at 119mm. The ZEISS Loxia 21mm F2.8 with a length of 72mm, is 47mm shorter. Besides being longer, the Sony FE 24-240mm F3.5-6.3 OSS also has a larger diameter of 81mm compared to the ZEISS Loxia 21mm F2.8's 62mm 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. ZEISS Loxia 21mm F2.8 weighs 394g, 49% (386g) lighter than the Sony FE 24-240mm F3.5-6.3 OSS's weight of 780g.
Filter Threads
The Sony FE 24-240mm F3.5-6.3 OSS has a filter size of 72mm whereas the ZEISS Loxia 21mm F2.8 has a 52mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 72mm filters that we recommend you to consider for the Sony FE 24-240mm F3.5-6.3 OSS:
And these are the 52mm filters that we recommend for the ZEISS Loxia 21mm F2.8:
Lens Mounts
Both the Sony FE 24-240mm F3.5-6.3 OSS 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 A9 III, Sony A7C Mark II and Sony A7CR.
Focal Range
Sony FE 24-240mm F3.5-6.3 OSS has a focal range of 24-240mm and
10.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
36 - 360mm.
On the other hand, the 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.