The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Panasonic S 35mm F1.8 and the Sigma 56mm F1.4 DC DN C 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. Panasonic S 35mm F1.8 is the longer of the two lenses at 82mm. The Sigma 56mm F1.4 DC DN C with a length of 60mm, is 22mm shorter. Besides being longer, the Panasonic S 35mm F1.8 also has a larger diameter of 74mm compared to the Sigma 56mm F1.4 DC DN C's 67mm 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 56mm F1.4 DC DN C weighs 280g, 5% (15g) lighter than the Panasonic S 35mm F1.8's weight of 295g.
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 the Panasonic S 35mm F1.8 and the Sigma 56mm F1.4 DC DN C 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 56mm F1.4 DC DN C is also available in Micro Four Thirds and Sony E mounts.
Panasonic S 35mm F1.8 is a prime lens with fixed focal lenght of 35mm. 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.