The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 17-50mm F2.8 EX DC OS HSM and the Canon 24-70mm f4L IS USM 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 24-70mm f4L IS USM is the longer of the two lenses at 93mm. The Sigma 17-50mm F2.8 EX DC OS HSM with a length of 92mm is 1mm shorter. On the other hand, the Sigma 17-50mm F2.8 EX DC OS HSM has a larger diameter of 84mm compared to Canon 24-70mm f4L IS USM's 83mm 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. Sigma 17-50mm F2.8 EX DC OS HSM weighs 565g, which means it is 35g (5%) lighter than the Canon 24-70mm f4L IS USM which has a weight of 600g.
Below you can find the dimension and weight table of the 'Standard Zoom Lenses in Canon EF Mount for size comparison purposes.
Standard Zoom Lenses in Canon EF Mount for Size Comparison
Both Sigma 17-50mm F2.8 EX DC OS HSM and Canon 24-70mm f4L IS USM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon T8i, Canon 90D and Canon SL3.
Sigma 17-50mm F2.8 EX DC OS HSM is also available in Pentax KAF3 , Sony Alpha, Sigma SA and Nikon F (DX) mounts.
Sigma 17-50mm F2.8 EX DC OS HSM has a focal range of 17-50mm and 2.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27.2-80mm when used on a APS-C / DX format camera. Canon 24-70mm f4L IS USM has a focal range of 24-70mm and 2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 38.4 - 112mm.