The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon EF 50mm f/1.8 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 EF 50mm f/1.8 STM with a length of 39mm, is 57mm 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 EF 50mm f/1.8 STM's 69mm 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 EF 50mm f/1.8 STM weighs 159g, which means it is 321g (66%) lighter than the Canon 18-135mm f3.5-5.6 IS STM which has a weight of 480g.
Filter Threads
The Canon EF 50mm f/1.8 STM has a filter size of 49mm whereas the Canon 18-135mm f3.5-5.6 IS STM has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 49mm filters that we recommend you to consider for the Canon EF 50mm f/1.8 STM:
And these are the 67mm filters that we recommend for the Canon 18-135mm f3.5-5.6 IS STM:
Lens Mounts
The Canon EF 50mm f/1.8 STM 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 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.
Focal Range
Canon EF 50mm f/1.8 STM is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
80mm.
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.
