The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 50mm F1.4 AS UMC 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. Samyang 50mm F1.4 AS UMC is the longer of the two lenses at 75mm. The Sigma 56mm F1.4 DC DN C with a length of 60mm, is 15mm shorter. Besides being longer, the Samyang 50mm F1.4 AS UMC also has a larger diameter of 82mm 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, 47% (255g) lighter than the Samyang 50mm F1.4 AS UMC's weight of 535g.
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
Lens Mounts
Both the Samyang 50mm F1.4 AS UMC and the 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 ZV-E1, Sony A7R V and Sony FX30.
Samyang 50mm F1.4 AS UMC is also available in Canon EF , Nikon F (FX), Pentax KAF and Sony Alpha mounts.
Sigma 56mm F1.4 DC DN C is also available in Micro Four Thirds and Leica L mounts.
Focal Range
Samyang 50mm F1.4 AS UMC 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 a 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.