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 Sigma 40mm F1.4 DG HSM A 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. Sigma 40mm F1.4 DG HSM A is the longer of the two lenses at 131mm. The Sigma 56mm F1.4 DC DN C with a length of 60mm, is 71mm shorter. Besides being longer, the Sigma 40mm F1.4 DG HSM A also has a larger diameter of 88mm 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.
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 56mm F1.4 DC DN C and the Sigma 40mm F1.4 DG HSM A 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 40mm F1.4 DG HSM A is also available in Canon EF , Nikon F (FX), Sigma SA and Sony E mounts.
Focal Range
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. Sigma 40mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 40mm.