The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 12-24mm F4.5-5.6 EX DG HSM and the Canon 17-40mm f4.0L 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 12-24mm F4.5-5.6 EX DG HSM is the longer of the two lenses at 103mm. The Canon 17-40mm f4.0L USM with a length of 97mm, is 6mm shorter. Besides being longer, the Sigma 12-24mm F4.5-5.6 EX DG HSM also has a larger diameter of 87mm compared to the Canon 17-40mm f4.0L USM's 84mm 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. Canon 17-40mm f4.0L USM weighs 500g, 16% (100g) lighter than the Sigma 12-24mm F4.5-5.6 EX DG HSM's weight of 600g.
Below you can find the dimension and weight table of the Wideangle Zoom Lenses in Canon EF Mount for size comparison purposes.
Ultra-Wideangle Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both the Sigma 12-24mm F4.5-5.6 EX DG HSM and the Canon 17-40mm f4.0L USM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Sigma 12-24mm F4.5-5.6 EX DG HSM is also available in Pentax KAF , Sony Alpha, Sigma SA and Nikon F (FX) mounts.
Focal Range
Sigma 12-24mm F4.5-5.6 EX DG HSM has a focal range of 12-24mm and
2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
19.2 - 38.4mm.
On the other hand, the Canon 17-40mm f4.0L USM has a focal range of 17-40mm and 2.4X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 27.2 - 64mm.