The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron AF 18-250mm f3.5-6.3 II LD and the Canon 18-200mm f3.5-5.6 IS 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 18-200mm f3.5-5.6 IS is the longer of the two lenses at 102mm. The Tamron AF 18-250mm f3.5-6.3 II LD with a length of 84mm is 18mm shorter. Besides being longer, the Canon 18-200mm f3.5-5.6 IS also has a larger diameter of 79mm compared to Tamron AF 18-250mm f3.5-6.3 II LD's 74mm 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. Tamron AF 18-250mm f3.5-6.3 II LD weighs 430g, which means it is 165g (27%) lighter than the Canon 18-200mm f3.5-5.6 IS which has a weight of 595g.
Lens Mounts
Both Tamron AF 18-250mm f3.5-6.3 II LD has the Canon EF lens mount whereas the Canon 18-200mm f3.5-5.6 IS 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.
Tamron AF 18-250mm f3.5-6.3 II LD is also available in Nikon F (DX) , Sony Alpha and Pentax KAF mounts.
Focal Range
Tamron AF 18-250mm f3.5-6.3 II LD has a focal range of 18-250mm and 13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 28.8-400mm when used on a APS-C / DX format camera. Canon 18-200mm f3.5-5.6 IS has a focal range of 18-200mm and 11.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 28.8-320mm when used on a APS-C / DX format camera.