The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-125mm F3.8-5.6 DC OS HSM and the Canon 18-200mm f3.5-5.6 IS 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 18-200mm f3.5-5.6 IS is the longer of the two lenses at 102mm. The Sigma 18-125mm F3.8-5.6 DC OS HSM with a length of 89mm, is 13mm shorter. Besides being longer, the Canon 18-200mm f3.5-5.6 IS also has a larger diameter of 79mm compared to the Sigma 18-125mm F3.8-5.6 DC OS HSM's 74mm 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. Sigma 18-125mm F3.8-5.6 DC OS HSM weighs 490g, which means it is 105g (17%) lighter than the Canon 18-200mm f3.5-5.6 IS which has a weight of 595g.
Filter Threads
The Sigma 18-125mm F3.8-5.6 DC OS HSM has a filter size of 67mm whereas the Canon 18-200mm f3.5-5.6 IS has a 72mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Sigma 18-125mm F3.8-5.6 DC OS HSM:
And these are the 72mm filters that we recommend for the Canon 18-200mm f3.5-5.6 IS:
Lens Mounts
The Sigma 18-125mm F3.8-5.6 DC OS HSM 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.
Sigma 18-125mm F3.8-5.6 DC OS HSM is also available in the Sigma SA and Nikon F (DX) mounts.
Focal Range
Sigma 18-125mm F3.8-5.6 DC OS HSM has a focal range of 18-125mm and
6.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
28.8-200mm when used on a APS-C / DX format camera.
On the other hand, the 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.
