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 Canon 55-250mm f4-5.6 IS STM 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 Canon 55-250mm f4-5.6 IS STM with a length of 111mm, is 11mm shorter. Besides being longer, the Samyang 135mm F2.0 ED UMC also has a larger diameter of 82mm compared to the Canon 55-250mm f4-5.6 IS STM's 70mm 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. Canon 55-250mm f4-5.6 IS STM weighs 375g, 54% (455g) lighter than the Samyang 135mm F2.0 ED UMC's weight of 830g.
Filter Threads
The Samyang 135mm F2.0 ED UMC has a filter size of 77mm whereas the Canon 55-250mm f4-5.6 IS STM has a 58mm 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 58mm filters that we recommend for the Canon 55-250mm f4-5.6 IS STM:
Lens Mounts
The Samyang 135mm F2.0 ED UMC has the Canon EF lens mount whereas the Canon 55-250mm f4-5.6 IS STM has the Canon EF-S lens mount. Some of the latest released cameras that are compatible with these mounts are Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount.
Samyang 135mm F2.0 ED UMC is also available in the Canon EF-M , Four Thirds, Fujifilm X, Micro Four Thirds, Nikon F (FX), Pentax KAF, Samsung NX, Sony Alpha 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 1.6x crop, it provides a 35mm (FF) equivalent of
216mm.
On the other hand, the Canon 55-250mm f4-5.6 IS STM has a focal range of 55-250mm and 4.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 88-400mm when used on a APS-C / DX format camera.