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 18-50mm F2.8-4.5 DC OS HSM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Sigma 18-50mm F2.8-4.5 DC OS HSM is the longer of the two lenses at 89mm. The Samyang 50mm F1.4 AS UMC with a length of 75mm, is 14mm shorter. On the other hand, the Samyang 50mm F1.4 AS UMC has a larger diameter of 82mm compared to the Sigma 18-50mm F2.8-4.5 DC OS HSM's 74mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Sigma 18-50mm F2.8-4.5 DC OS HSM weighs 395g, 26% (140g) lighter than the Samyang 50mm F1.4 AS UMC's weight of 535g.
Filter Threads
The Samyang 50mm F1.4 AS UMC has a filter size of 77mm whereas the Sigma 18-50mm F2.8-4.5 DC OS HSM has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Samyang 50mm F1.4 AS UMC:
And these are the 67mm filters that we recommend for the Sigma 18-50mm F2.8-4.5 DC OS HSM:
Lens Mounts
Both the Samyang 50mm F1.4 AS UMC and the Sigma 18-50mm F2.8-4.5 DC OS HSM has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are , and .
Samyang 50mm F1.4 AS UMC is also available in the Canon EF , Nikon F (FX), Pentax KAF and Sony E mounts.
Sigma 18-50mm F2.8-4.5 DC OS HSM is also available in Canon EF , Pentax KAF3, Sigma SA and Nikon F (DX) 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.
On the other hand, the Sigma 18-50mm F2.8-4.5 DC OS HSM has a focal range of 18-50mm and 2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-75mm when used on a APS-C / DX format camera.
