The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 24-85mm f3.5-4.5 USM and the Tamron 24-70mm F2.8 Di VC USD G2 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 24-70mm F2.8 Di VC USD G2 is the longer of the two lenses at 111mm. The Canon 24-85mm f3.5-4.5 USM with a length of 70mm, is 41mm shorter. Besides being longer, the Tamron 24-70mm F2.8 Di VC USD G2 also has a larger diameter of 88mm compared to the Canon 24-85mm f3.5-4.5 USM's 73mm 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 24-85mm f3.5-4.5 USM weighs 380g, which means it is 525g (58%) lighter than the Tamron 24-70mm F2.8 Di VC USD G2 which has a weight of 905g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Canon EF Mount for size comparison purposes.
Standard Lenses in Canon EF Mount for Size Comparison
Filter Threads
The Canon 24-85mm f3.5-4.5 USM has a filter size of 67mm whereas the Tamron 24-70mm F2.8 Di VC USD G2 has a 82mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Canon 24-85mm f3.5-4.5 USM:
And these are the 82mm filters that we recommend for the Tamron 24-70mm F2.8 Di VC USD G2:
Lens Mounts
Both the Canon 24-85mm f3.5-4.5 USM and the Tamron 24-70mm F2.8 Di VC USD G2 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 Di VC USD G2 is also available in Nikon F (FX) mount.
Focal Range
Canon 24-85mm f3.5-4.5 USM has a focal range of 24-85mm and
3.5X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
38.4 - 136mm.
On the other hand, the Tamron 24-70mm F2.8 Di VC USD G2 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 a 35mm (FF) equivalent of 38.4 - 112mm.