The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 70-300mm f4-5.6 VC USD and the Canon 75-300mm f4.0-5.6 III 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. Tamron 70-300mm f4-5.6 VC USD is the longer of the two lenses at 143mm. The Canon 75-300mm f4.0-5.6 III USM with a length of 122mm, is 21mm shorter. Besides being longer, the Tamron 70-300mm f4-5.6 VC USD also has a larger diameter of 82mm compared to the Canon 75-300mm f4.0-5.6 III USM's 71mm 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 75-300mm f4.0-5.6 III USM weighs 480g, 37% (285g) lighter than the Tamron 70-300mm f4-5.6 VC USD's weight of 765g.
Below you can find the dimension and weight table of the Telephoto Zoom Lenses in Canon EF Mount for size comparison purposes.
Telephoto Lenses in Canon EF Mount for Size Comparison
Filter Threads
The Tamron 70-300mm f4-5.6 VC USD has a filter size of 62mm whereas the Canon 75-300mm f4.0-5.6 III USM has a 58mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 62mm filters that we recommend you to consider for the Tamron 70-300mm f4-5.6 VC USD:
And these are the 58mm filters that we recommend for the Canon 75-300mm f4.0-5.6 III USM:
Lens Mounts
Both the Tamron 70-300mm f4-5.6 VC USD and the Canon 75-300mm f4.0-5.6 III 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 70-300mm f4-5.6 VC USD is also available in Nikon F (FX) mount.
Focal Range
Tamron 70-300mm f4-5.6 VC USD has a focal range of 70-300mm and
4.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
112 - 480mm.
On the other hand, the Canon 75-300mm f4.0-5.6 III USM has a focal range of 75-300mm and 4.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 120 - 480mm.