The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang AF 18mm F2.8 FE and the Sigma 28mm 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 28mm F1.4 DG HSM A is the longer of the two lenses at 108mm. The Samyang AF 18mm F2.8 FE with a length of 61mm, is 47mm shorter. Besides being longer, the Sigma 28mm F1.4 DG HSM A also has a larger diameter of 83mm compared to the Samyang AF 18mm F2.8 FE's 64mm 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 Wideangle Prime Lenses in Sony E Mount for size comparison purposes.
Wideangle Prime Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both the Samyang AF 18mm F2.8 FE and the Sigma 28mm F1.4 DG HSM A 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 28mm F1.4 DG HSM A is also available in Canon EF , Nikon F (FX), Sigma SA and Leica L mounts.
Focal Range
Samyang AF 18mm F2.8 FE is a prime lens with fixed focal lenght of 18mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 27mm.
Sigma 28mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 28mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 42mm.