The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 10-18mm f4.5-5.6 IS STM and the Canon 18-135mm f3.5-5.6 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. Canon 18-135mm f3.5-5.6 IS STM is the longer of the two lenses at 96mm. The Canon 10-18mm f4.5-5.6 IS STM with a length of 72mm, is 24mm shorter. Besides being longer, the Canon 18-135mm f3.5-5.6 IS STM also has a larger diameter of 77mm compared to the Canon 10-18mm f4.5-5.6 IS STM's 75mm 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 10-18mm f4.5-5.6 IS STM weighs 240g, which means it is 240g (50%) lighter than the Canon 18-135mm f3.5-5.6 IS STM which has a weight of 480g.
Filter Threads
Both the Canon 10-18mm f4.5-5.6 IS STM and the Canon 18-135mm f3.5-5.6 IS STM have the same Filter thread size of 67mm.
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Canon 10-18mm f4.5-5.6 IS STM and the Canon 18-135mm f3.5-5.6 IS STM has the same Canon EF-S lens mount. Some of the latest released cameras that are compatible with the Canon EF-S lenses are Canon T8i, Canon 90D and Canon SL3.
Focal Range
Canon 10-18mm f4.5-5.6 IS STM has a focal range of 10-18mm and
1.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
16-28.8mm when used on a APS-C / DX format camera.
On the other hand, the 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.
