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 Leica APO-SL 28mm F2 ASPH 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 Leica APO-SL 28mm F2 ASPH with a length of 102mm, is 9mm shorter. Besides being longer, the Sigma 20mm F1.4 DG DN A also has a larger diameter of 88mm compared to the Leica APO-SL 28mm F2 ASPH's 73mm diameter.
ss
Below you can find a scaled side-by-side image of Sigma 20mm F1.4 DG DN A and Leica APO-SL 28mm F2 ASPH 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. Sigma 20mm F1.4 DG DN A weighs 635g, which means it is 65g (9%) lighter than the Leica APO-SL 28mm F2 ASPH which has a weight of 700g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Leica L Mount for size comparison purposes.
Wideangle Lenses in Leica L Mount for Size Comparison
Filter Threads
The Sigma 20mm F1.4 DG DN A has a filter size of 82mm whereas the Leica APO-SL 28mm F2 ASPH has a 67mm 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 67mm filters that we recommend for the Leica APO-SL 28mm F2 ASPH:
Lens Mounts
Both the Sigma 20mm F1.4 DG DN A and the Leica APO-SL 28mm F2 ASPH has the same Leica L lens mount. Some of the latest released cameras that are compatible with the Leica L lenses are Leica SL3, Panasonic S5 II and Panasonic S5 II X.
Sigma 20mm F1.4 DG DN A is also available in Sony E 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 Leica APO-SL 28mm F2 ASPH is a prime lens with fixed focal lenght of 28mm.