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 Tamron 10-24mm f3.5-4.5 II LD for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Tamron 10-24mm f3.5-4.5 II LD is the longer of the two lenses at 79mm. The Canon 10-18mm f4.5-5.6 IS STM with a length of 72mm is 7mm shorter. Besides being longer, the Tamron 10-24mm f3.5-4.5 II LD also has a larger diameter of 83mm compared to Canon 10-18mm f4.5-5.6 IS STM's 75mm 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 10-18mm f4.5-5.6 IS STM weighs 240g, which means it is 115g (32%) lighter than the Tamron 10-24mm f3.5-4.5 II LD which has a weight of 355g.
Lens Mounts
Both Canon 10-18mm f4.5-5.6 IS STM has the Canon EF-S lens mount whereas the Tamron 10-24mm f3.5-4.5 II LD has the Canon EF 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-S Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount.
Tamron 10-24mm f3.5-4.5 II LD is also available in Canon EF , Nikon F (DX), Sony Alpha and Pentax KAF mounts.
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. Tamron 10-24mm f3.5-4.5 II LD has a focal range of 11-18mm and 1.6X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 17.6-28.8mm when used on a APS-C / DX format camera.