The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 20mm F1.8 and the Tokina 16.5-135mm f3.5-5.6 DX 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 20mm F1.8 is the longer of the two lenses at 88mm. The Tokina 16.5-135mm f3.5-5.6 DX with a length of 78mm, is 10mm shorter. On the other hand, the Tokina 16.5-135mm f3.5-5.6 DX has a larger diameter of 84mm compared to the Samyang 20mm F1.8's 83mm 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 20mm F1.8 weighs 497g, which means it is 113g (18%) lighter than the Tokina 16.5-135mm f3.5-5.6 DX which has a weight of 610g.
Filter Threads
Both the Samyang 20mm F1.8 and the Tokina 16.5-135mm f3.5-5.6 DX have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Samyang 20mm F1.8 and the Tokina 16.5-135mm f3.5-5.6 DX has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Samyang 20mm F1.8 is also available in Canon EF-M , Fujifilm X, Micro Four Thirds, Nikon F (FX), Pentax KAF, Samsung NX, Sony Alpha and Sony E mounts.
Tokina 16.5-135mm f3.5-5.6 DX is also available in Nikon F (DX) mount.
Focal Range
Samyang 20mm F1.8 is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
32mm.
On the other hand, the Tokina 16.5-135mm f3.5-5.6 DX has a focal range of 17-135mm and 7.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27.2-216mm when used on a APS-C / DX format camera.