The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 50mm F1.4 FE II and the Sigma 56mm F1.4 DC DN C for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Samyang 50mm F1.4 FE II is the longer of the two lenses at 89mm. The Sigma 56mm F1.4 DC DN C with a length of 60mm is 29mm shorter. Besides being longer, the Samyang 50mm F1.4 FE II also has a larger diameter of 80mm 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, 33% (140g) lighter than the Samyang 50mm F1.4 FE II's weight of 420g.
Below you can find the dimension and weight table of the 'Standard Prime Lenses in Sony E Mount for size comparison purposes.
Standard Prime Lenses in Sony E Mount for Size Comparison
Both Samyang 50mm F1.4 FE II and Sigma 56mm F1.4 DC DN C has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A7R V, Sony FX30 and Sony A7 IV.
Sigma 56mm F1.4 DC DN C is also available in Micro Four Thirds and Leica L mounts.
Samyang 50mm F1.4 FE II is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 75mm.
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.