The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 30mm F1.4 DC HSM and the Samyang 35mm F1.4 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 35mm F1.4 is the longer of the two lenses at 112mm. The Sigma 30mm F1.4 DC HSM with a length of 63mm, is 49mm shorter. On the other hand, the Sigma 30mm F1.4 DC HSM has a larger diameter of 74mm compared to the Samyang 35mm F1.4's 63mm 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 30mm F1.4 DC HSM weighs 435g, which means it is 225g (34%) lighter than the Samyang 35mm F1.4 which has a weight of 660g.
Lens Mounts
The Sigma 30mm F1.4 DC HSM has the Nikon F (DX) lens mount whereas the Samyang 35mm F1.4 has the Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount and Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount.
Sigma 30mm F1.4 DC HSM is also available in Canon EF and Sigma SA mounts.
Samyang 35mm F1.4 is also available in Canon EF , Four Thirds, Pentax KAF, Sony Alpha, Sony E and Samsung NX mounts.
Focal Range
Sigma 30mm F1.4 DC HSM is a prime lens with fixed focal lenght of 30mm which has an effective (full-frame 35mm equivalent) focal range of 45mm when used on a APS-C / DX format camera. Samyang 35mm F1.4 is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 52.5mm.