The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 24-70mm f2.8 VC USD and the Canon 35-80mm f4.0-5.6 III 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 24-70mm f2.8 VC USD is the longer of the two lenses at 117mm. The Canon 35-80mm f4.0-5.6 III with a length of 64mm is 53mm shorter. Besides being longer, the Tamron 24-70mm f2.8 VC USD also has a larger diameter of 88mm compared to Canon 35-80mm f4.0-5.6 III's 65mm 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 35-80mm f4.0-5.6 III weighs 175g, 78% (650g) lighter than the Tamron 24-70mm f2.8 VC USD's weight of 825g.
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 Tamron 24-70mm f2.8 VC USD and Canon 35-80mm f4.0-5.6 III 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 24-70mm f2.8 VC USD is also available in Nikon F (FX) and Sony Alpha mounts.
Tamron 24-70mm f2.8 VC USD 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.
Canon 35-80mm f4.0-5.6 III has a focal range of 35-80mm and 2.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 56 - 128mm.