The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang AF 135mm F1.8 FE and the Sigma 105mm F1.4 DG HSM 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 105mm F1.4 DG HSM is the longer of the two lenses at 132mm. The Samyang AF 135mm F1.8 FE with a length of 130mm, is 2mm shorter. Besides being longer, the Sigma 105mm F1.4 DG HSM also has a larger diameter of 116mm compared to the Samyang AF 135mm F1.8 FE's 93mm 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. Samyang AF 135mm F1.8 FE weighs 772g, which means it is 873g (53%) lighter than the Sigma 105mm F1.4 DG HSM which has a weight of 1645g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Sony E Mount for size comparison purposes.
Telephoto Prime Lenses in Sony E Mount for Size Comparison
Both the Samyang AF 135mm F1.8 FE and the Sigma 105mm F1.4 DG HSM 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.
Sigma 105mm F1.4 DG HSM is also available in Canon EF , Nikon F (FX) and Sigma SA mounts.
Samyang AF 135mm F1.8 FE is a prime lens with fixed focal lenght of 135mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 202.5mm.
Sigma 105mm F1.4 DG HSM is a prime lens with fixed focal lenght of 105mm which has an effective (full-frame 35mm equivalent) focal range of 157.5mm when used on a 35mm FF format camera.