The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 20mm F1.4 DG DN A and the Zeiss Loxia 25mm F2.4 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. Sigma 20mm F1.4 DG DN A is the longer of the two lenses at 111mm. The Zeiss Loxia 25mm F2.4 with a length of 75mm, is 36mm shorter. Besides being longer, the Sigma 20mm F1.4 DG DN A also has a larger diameter of 88mm compared to the Zeiss Loxia 25mm F2.4's 62mm diameter.
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Below you can find a scaled side-by-side image of Sigma 20mm F1.4 DG DN A and Zeiss Loxia 25mm F2.4 to get a better idea of how their sizes compare in real life.
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 25mm F2.4 weighs 393g, 38% (242g) lighter than the Sigma 20mm F1.4 DG DN A's weight of 635g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Sony E Mount for size comparison purposes.
Wideangle Lenses in Sony E Mount for Size Comparison
Filter Threads
The Sigma 20mm F1.4 DG DN A has a filter size of 82mm whereas the Zeiss Loxia 25mm F2.4 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 82mm filters that we recommend you to consider for the Sigma 20mm F1.4 DG DN A:
And these are the 52mm filters that we recommend for the Zeiss Loxia 25mm F2.4:
Lens Mounts
Both the Sigma 20mm F1.4 DG DN A and the Zeiss Loxia 25mm F2.4 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.
Sigma 20mm F1.4 DG DN A is also available in Leica L mount.
Focal Range
Sigma 20mm F1.4 DG DN A 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
36mm.
On the other hand, the Zeiss Loxia 25mm F2.4 is a prime lens with fixed focal lenght of 25mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 37.5mm.