The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 85mm F1.8 ED UMC CS and the Sony FE 135mm F1.8 GM 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. Sony FE 135mm F1.8 GM is the longer of the two lenses at 127mm. The Samyang 85mm F1.8 ED UMC CS with a length of 81mm, is 46mm shorter. Besides being longer, the Sony FE 135mm F1.8 GM also has a larger diameter of 90mm compared to the Samyang 85mm F1.8 ED UMC CS's 68mm diameter.
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Below you can find a scaled side-by-side image of Samyang 85mm F1.8 ED UMC CS and Sony FE 135mm F1.8 GM 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 85mm F1.8 ED UMC CS weighs 344g, which means it is 606g (63%) lighter than the Sony FE 135mm F1.8 GM which has a weight of 950g.
Below you can find the dimension and weight table of the Telephoto Prime Lenses in Sony E Mount for size comparison purposes.
Telephoto Lenses in Sony E Mount for Size Comparison
Filter Threads
The Samyang 85mm F1.8 ED UMC CS has a filter size of 62mm whereas the Sony FE 135mm F1.8 GM has a 82mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 62mm filters that we recommend you to consider for the Samyang 85mm F1.8 ED UMC CS:
And these are the 82mm filters that we recommend for the Sony FE 135mm F1.8 GM:
Lens Mounts
Both the Samyang 85mm F1.8 ED UMC CS and the Sony FE 135mm F1.8 GM has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A6700, Sony FX30 and Sony ZV-E10.
Samyang 85mm F1.8 ED UMC CS is also available in Canon EF-M and Fujifilm X mounts.
Focal Range
Samyang 85mm F1.8 ED UMC CS is a prime lens with fixed focal lenght of 85mm which has an effective (full-frame 35mm equivalent) focal range of
127.5mm when used on a APS-C / DX format camera.
On the other hand, the Sony FE 135mm F1.8 GM 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.