The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 135mm F2.0 ED UMC and the Samyang 50mm F1.2 AS UMC CS 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. Samyang 135mm F2.0 ED UMC is the longer of the two lenses at 122mm. The Samyang 50mm F1.2 AS UMC CS with a length of 74mm, is 48mm shorter. Besides being longer, the Samyang 135mm F2.0 ED UMC also has a larger diameter of 82mm compared to the Samyang 50mm F1.2 AS UMC CS's 68mm diameter.
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Below you can find a scaled side-by-side image of Samyang 135mm F2.0 ED UMC and Samyang 50mm F1.2 AS UMC CS to get a better idea of how their sizes compare in real life.
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. Samyang 50mm F1.2 AS UMC CS weighs 375g, 54% (455g) lighter than the Samyang 135mm F2.0 ED UMC's weight of 830g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Fujifilm X Mount for size comparison purposes.
Telephoto Lenses in Fujifilm X Mount for Size Comparison
Filter Threads
The Samyang 135mm F2.0 ED UMC has a filter size of 77mm whereas the Samyang 50mm F1.2 AS UMC CS has a 62mm 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 135mm F2.0 ED UMC:
And these are the 62mm filters that we recommend for the Samyang 50mm F1.2 AS UMC CS:
Lens Mounts
Both the Samyang 135mm F2.0 ED UMC and the Samyang 50mm F1.2 AS UMC CS has the same Fujifilm X lens mount. Some of the latest released cameras that are compatible with the Fujifilm X lenses are Fujifilm X-S20, Fujifilm X-T5 and Fujifilm X-H2.
Samyang 135mm F2.0 ED UMC is also available in Canon EF , Canon EF-M, Four Thirds, Micro Four Thirds, Nikon F (FX), Pentax KAF, Samsung NX, Sony Alpha and Sony E mounts.
Samyang 50mm F1.2 AS UMC CS is also available in Canon EF-M , Micro Four Thirds and Sony E mounts.
Focal Range
Samyang 135mm F2.0 ED UMC 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.
On the other hand, the Samyang 50mm F1.2 AS UMC CS is a prime lens with fixed focal lenght of 50mm which has an effective (full-frame 35mm equivalent) focal range of 75mm when used on a APS-C / DX format camera.