The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 45mm F2.8 DG DN C and the Leica APO-SL 50mm F2 ASPH 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. Leica APO-SL 50mm F2 ASPH is the longer of the two lenses at 102mm. The Sigma 45mm F2.8 DG DN C with a length of 46mm, is 56mm shorter. Besides being longer, the Leica APO-SL 50mm F2 ASPH also has a larger diameter of 73mm compared to the Sigma 45mm F2.8 DG DN C's 64mm 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. Sigma 45mm F2.8 DG DN C weighs 215g, which means it is 525g (70%) lighter than the Leica APO-SL 50mm F2 ASPH which has a weight of 740g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Leica L Mount for size comparison purposes.
Standard Prime Lenses in Leica L Mount for Size Comparison
Lens Mounts
Both the Sigma 45mm F2.8 DG DN C and the Leica APO-SL 50mm F2 ASPH has the same Leica L lens mount. Some of the latest released cameras that are compatible with the Leica L lenses are Panasonic S5 II, Panasonic S5 II X and Sigma fp L.
Sigma 45mm F2.8 DG DN C is also available in Sony E mount.
Focal Range
Sigma 45mm F2.8 DG DN C is a prime lens with fixed focal lenght of 45mm. Leica APO-SL 50mm F2 ASPH is a prime lens with fixed focal lenght of 50mm.