The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tokina 16.5-135mm f3.5-5.6 DX and the Canon 18-135mm f3.5-5.6 IS STM for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Canon 18-135mm f3.5-5.6 IS STM is the longer of the two lenses at 96mm. The Tokina 16.5-135mm f3.5-5.6 DX with a length of 78mm is 18mm shorter. On the other hand, the Tokina 16.5-135mm f3.5-5.6 DX has a larger diameter of 84mm compared to Canon 18-135mm f3.5-5.6 IS STM's 77mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Canon 18-135mm f3.5-5.6 IS STM weighs 480g, 21% (130g) lighter than the Tokina 16.5-135mm f3.5-5.6 DX's weight of 610g.
Lens Mounts
Both Tokina 16.5-135mm f3.5-5.6 DX has the Canon EF lens mount whereas the Canon 18-135mm f3.5-5.6 IS STM has the Canon EF-S lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount.
Tokina 16.5-135mm f3.5-5.6 DX is also available in Nikon F (DX) mount.
Focal Range
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. Canon 18-135mm f3.5-5.6 IS STM has a focal range of 18-135mm and 7.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 28.8-216mm when used on a APS-C / DX format camera.