The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron SP 15-30mm F2.8 Di VC USD G2 and the Sigma 12-24mm F4.5-5.6 II DG HSM 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. Tamron SP 15-30mm F2.8 Di VC USD G2 is the longer of the two lenses at 145mm. The Sigma 12-24mm F4.5-5.6 II DG HSM with a length of 120mm, is 25mm shorter. Besides being longer, the Tamron SP 15-30mm F2.8 Di VC USD G2 also has a larger diameter of 98mm compared to the Sigma 12-24mm F4.5-5.6 II DG HSM's 87mm 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 12-24mm F4.5-5.6 II DG HSM weighs 670g, 39% (440g) lighter than the Tamron SP 15-30mm F2.8 Di VC USD G2's weight of 1110g.
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 Tamron SP 15-30mm F2.8 Di VC USD G2 and the Sigma 12-24mm F4.5-5.6 II DG HSM 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.
Tamron SP 15-30mm F2.8 Di VC USD G2 is also available in Nikon F (FX) mount.
Sigma 12-24mm F4.5-5.6 II DG HSM is also available in Sigma SA and Nikon F (FX) mounts.
Focal Range
Tamron SP 15-30mm F2.8 Di VC USD G2 has a focal range of 15-30mm 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
24 - 48mm.
On the other hand, the Sigma 12-24mm F4.5-5.6 II 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.