The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 15-30mm f2.8 VC USD and the Canon 17-40mm f4.0L 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.Tamron 15-30mm f2.8 VC USD is the longer of the two lenses at 145mm. The Canon 17-40mm f4.0L USM with a length of 97mm is 48mm shorter. Besides being longer, the Tamron 15-30mm f2.8 VC USD also has a larger diameter of 98mm compared to Canon 17-40mm f4.0L USM's 84mm 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. Canon 17-40mm f4.0L USM weighs 500g, 54% (600g) lighter than the Tamron 15-30mm f2.8 VC USD's weight of 1100g.
Below you can find the dimension and weight table of the 'Wideangle Zoom Lenses in Canon EF Mount for size comparison purposes.
Wideangle Zoom Lenses in Canon EF Mount for Size Comparison
Both Tamron 15-30mm f2.8 VC USD and 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.
Tamron 15-30mm f2.8 VC USD is also available in Nikon F (FX) and Sony Alpha mounts.
Tamron 15-30mm f2.8 VC USD 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 an 35mm (FF) equivalent of 24 - 48mm.
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 an 35mm (FF) equivalent of 27.2 - 64mm.