The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-200mm f3.5-6.3 II DC OS HSM and the Canon 15-85mm f3.5-5.6 IS USM for their suitability to various photography scenarios:
Size and Weight Comparison
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 18-200mm f3.5-6.3 II DC OS HSM weighs 490g, which means it is 85g (14%) lighter than the Canon 15-85mm f3.5-5.6 IS USM which has a weight of 575g.
Filter Threads
The Sigma 18-200mm f3.5-6.3 II DC OS HSM has a filter size of 62mm whereas the Canon 15-85mm f3.5-5.6 IS USM 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 62mm filters that we recommend you to consider for the Sigma 18-200mm f3.5-6.3 II DC OS HSM:
And these are the 72mm filters that we recommend for the Canon 15-85mm f3.5-5.6 IS USM:
Lens Mounts
The Sigma 18-200mm f3.5-6.3 II DC OS HSM has the Canon EF lens mount whereas the Canon 15-85mm f3.5-5.6 IS USM 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 18-200mm f3.5-6.3 II DC OS HSM is also available in the Nikon F (DX) and Sigma SA mounts.
Focal Range
Sigma 18-200mm f3.5-6.3 II DC OS HSM 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.
On the other hand, the Canon 15-85mm f3.5-5.6 IS USM has a focal range of 15-85mm and 5.7X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 24-136mm when used on a APS-C / DX format camera.
