The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 100-400mm F4.5-6.3 Di VC USD and the Sigma 300-800mm F5.6 EX DG HSM 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. Sigma 300-800mm F5.6 EX DG HSM is the longer of the two lenses at 544mm. The Tamron 100-400mm F4.5-6.3 Di VC USD with a length of 199mm, is 345mm shorter. Besides being longer, the Sigma 300-800mm F5.6 EX DG HSM also has a larger diameter of 157mm compared to the Tamron 100-400mm F4.5-6.3 Di VC USD's 86mm 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. Tamron 100-400mm F4.5-6.3 Di VC USD weighs 1135g, which means it is 4745g (80%) lighter than the Sigma 300-800mm F5.6 EX DG HSM which has a 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.
Super Telephoto Lenses in Nikon F (FX) Mount for Size Comparison
Filter Threads
The Tamron 100-400mm F4.5-6.3 Di VC USD has a filter size of 67mm whereas the Sigma 300-800mm F5.6 EX DG HSM has a 46mm 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 Tamron 100-400mm F4.5-6.3 Di VC USD:
And these are the 46mm filters that we recommend for the Sigma 300-800mm F5.6 EX DG HSM:
Lens Mounts
Both the Tamron 100-400mm F4.5-6.3 Di VC USD and the Sigma 300-800mm F5.6 EX DG HSM 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.
Tamron 100-400mm F4.5-6.3 Di VC USD is also available in Canon EF mount.
Sigma 300-800mm F5.6 EX DG HSM is also available in Sigma SA and Canon EF mounts.
Focal Range
Tamron 100-400mm F4.5-6.3 Di VC USD has a focal range of 100-400mm 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
150 - 600mm.
On the other hand, the 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.