The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 300-800mm F5.6 EX DG HSM and the Tamron 70-200mm f2.8 VC USD 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. Sigma 300-800mm F5.6 EX DG HSM is the longer of the two lenses at 544mm. The Tamron 70-200mm f2.8 VC USD with a length of 197mm, is 347mm shorter. Besides being longer, the Sigma 300-800mm F5.6 EX DG HSM also has a larger diameter of 157mm compared to the Tamron 70-200mm f2.8 VC USD's 86mm 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. Tamron 70-200mm f2.8 VC USD weighs 1470g, 75% (4410g) lighter than the Sigma 300-800mm F5.6 EX DG HSM's weight of 5880g.
Below you can find the dimension and weight table of the Telephoto Zoom Lenses in Nikon F (FX) Mount for size comparison purposes.
Telephoto Zoom Lenses in Nikon F (FX) Mount for Size Comparison
Lens Mounts
Both the Sigma 300-800mm F5.6 EX DG HSM and the Tamron 70-200mm f2.8 VC USD has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Sigma 300-800mm F5.6 EX DG HSM is also available in Sigma SA and Canon EF mounts.
Tamron 70-200mm f2.8 VC USD is also available in Canon EF and Sony Alpha mounts.
Focal Range
Sigma 300-800mm F5.6 EX DG HSM has a focal range of 300-800mm and 2.7X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 450 - 1200mm.
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.