The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 70-200mm f2.8 VC USD and the Sony 75-300mm F4.5-5.6 for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Tamron 70-200mm f2.8 VC USD is the longer of the two lenses at 197mm. The Sony 75-300mm F4.5-5.6 with a length of 122mm, is 75mm shorter. Besides being longer, the Tamron 70-200mm f2.8 VC USD also has a larger diameter of 86mm compared to the Sony 75-300mm F4.5-5.6's 71mm diameter.
The 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. Sony 75-300mm F4.5-5.6 weighs 460g, 68% (1010g) lighter than the Tamron 70-200mm f2.8 VC USD's weight of 1470g.
Below you can find the dimension and weight table of the Telephoto Zoom Lenses in Sony Alpha Mount for size comparison purposes.
Telephoto Zoom Lenses in Sony Alpha Mount for Size Comparison
Lens Mounts
Both the Tamron 70-200mm f2.8 VC USD and the Sony 75-300mm F4.5-5.6 has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A99 II, Sony A68 and Sony A77 II.
Tamron 70-200mm f2.8 VC USD is also available in Canon EF and Nikon F (FX) mounts.
Focal Range
Tamron 70-200mm f2.8 VC USD has a focal range of 70-200mm and 2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 105 - 300mm.
Sony 75-300mm F4.5-5.6 has a focal range of 75-300mm and 4.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 112.5 - 450mm.