The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 21mm F1.4 ED AS UMC CS and the Sony DT 18-135mm F3.5-5.6 SAM 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 DT 18-135mm F3.5-5.6 SAM is the longer of the two lenses at 86mm. The Samyang 21mm F1.4 ED AS UMC CS with a length of 68mm, is 18mm shorter. Besides being longer, the Sony DT 18-135mm F3.5-5.6 SAM also has a larger diameter of 76mm compared to the Samyang 21mm F1.4 ED AS UMC CS's 64mm 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. Samyang 21mm F1.4 ED AS UMC CS weighs 275g, which means it is 123g (30%) lighter than the Sony DT 18-135mm F3.5-5.6 SAM which has a weight of 398g.
Filter Threads
The Samyang 21mm F1.4 ED AS UMC CS has a filter size of 58mm whereas the Sony DT 18-135mm F3.5-5.6 SAM 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 58mm filters that we recommend you to consider for the Samyang 21mm F1.4 ED AS UMC CS:
And these are the 62mm filters that we recommend for the Sony DT 18-135mm F3.5-5.6 SAM:
Lens Mounts
The Samyang 21mm F1.4 ED AS UMC CS has the Fujifilm X lens mount whereas the Sony DT 18-135mm F3.5-5.6 SAM has the Sony Alpha lens mount. Some of the latest released cameras that are compatible with these mounts are Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5 for the Fujifilm X Mount and Sony A68, Sony A77 II and Sony A58 for the Sony Alpha Mount.
Samyang 21mm F1.4 ED AS UMC CS is also available in the Canon EF-M , Micro Four Thirds and Sony E mounts.
Focal Range
Samyang 21mm F1.4 ED AS UMC CS is a prime lens with fixed focal lenght of 21mm which has an effective (full-frame 35mm equivalent) focal range of
31.5mm when used on a APS-C / DX format camera.
On the other hand, the Sony DT 18-135mm F3.5-5.6 SAM has a focal range of 18-135mm and 7.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-202.5mm when used on a APS-C / DX format camera.
