The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 56mm F1.4 DC DN C and the Leica APO-Summicron-SL 50mm F2 ASPH for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Leica APO-Summicron-SL 50mm F2 ASPH is the longer of the two lenses at 102mm. The Sigma 56mm F1.4 DC DN C with a length of 60mm is 42mm shorter. Besides being longer, the Leica APO-Summicron-SL 50mm F2 ASPH also has a larger diameter of 73mm compared to Sigma 56mm F1.4 DC DN C's 67mm diameter.
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 56mm F1.4 DC DN C weighs 280g, which means it is 460g (62%) lighter than the Leica APO-Summicron-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
Both Sigma 56mm F1.4 DC DN C and Leica APO-Summicron-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 Leica TL2, Leica TL and Leica T Typ 701.
Sigma 56mm F1.4 DC DN C is also available in Micro Four Thirds and Sony E mounts.
Sigma 56mm F1.4 DC DN C is a prime lens with fixed focal lenght of 56mm which has an effective (full-frame 35mm equivalent) focal range of 84mm when used on a APS-C / DX format camera. Leica APO-Summicron-SL 50mm F2 ASPH is a prime lens with fixed focal lenght of 50mm.