The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 40mm F1.4 DG HSM A and the Samyang 35mm F1.2 for their suitability to various photography scenarios:
Size and Weight Comparison
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 Samyang 35mm F1.2 with a length of 74mm is 57mm shorter. Besides being longer, the Sigma 40mm F1.4 DG HSM A also has a larger diameter of 88mm compared to Samyang 35mm F1.2's 68mm 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.
Lens Mounts
Both Sigma 40mm F1.4 DG HSM A and Samyang 35mm F1.2 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 40mm F1.4 DG HSM A is also available in Canon EF , Nikon F (FX), Sigma SA and Leica L mounts.
Samyang 35mm F1.2 is also available in Canon EF-M , Fujifilm X and Micro Four Thirds mounts.
Focal Range
Sigma 40mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 40mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 60mm.
Samyang 35mm F1.2 is a prime lens with fixed focal lenght of 35mm which has an effective (full-frame 35mm equivalent) focal range of 52.5mm when used on a APS-C / DX format camera.