The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 17-70mm F2.8-4 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 size of a lens is a crucial factor to consider when comparing two lenses. Sigma 17-70mm F2.8-4 DC OS HSM is the longer of the two lenses at 89mm. The Canon 15-85mm f3.5-5.6 IS USM with a length of 88mm, is 1mm shorter. On the other hand, the Canon 15-85mm f3.5-5.6 IS USM has a larger diameter of 82mm compared to the Sigma 17-70mm F2.8-4 DC OS HSM's 79mm 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 17-70mm F2.8-4 DC OS HSM weighs 520g, which means it is 55g (9%) lighter than the Canon 15-85mm f3.5-5.6 IS USM which has a weight of 575g.
Filter Threads
Both the Sigma 17-70mm F2.8-4 DC OS HSM and the Canon 15-85mm f3.5-5.6 IS USM have the same Filter thread size of 72mm.
Below are links to the 72mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Sigma 17-70mm F2.8-4 DC OS HSM has the Sigma SA 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 Sigma SD1 Merrill, Sigma SD1 and for the Sigma SA Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount.
Sigma 17-70mm F2.8-4 DC OS HSM is also available in the Canon EF , Pentax KAF3, Sony Alpha and Nikon F (DX) mounts.
Focal Range
Sigma 17-70mm F2.8-4 DC OS HSM has a focal range of 17-70mm and
4.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
25.5-105mm 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.
