The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 120-400mm F4.5-5.6 DG OS HSM and the Nikon 80-400mm f4.5-5.6D ED VR 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 120-400mm F4.5-5.6 DG OS HSM is the longer of the two lenses at 203mm. The Nikon 80-400mm f4.5-5.6D ED VR with a length of 171mm, is 32mm shorter. Besides being longer, the Sigma 120-400mm F4.5-5.6 DG OS HSM also has a larger diameter of 92mm compared to the Nikon 80-400mm f4.5-5.6D ED VR's 91mm 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. Nikon 80-400mm f4.5-5.6D ED VR weighs 1340g, 18% (300g) lighter than the Sigma 120-400mm F4.5-5.6 DG OS HSM's weight of 1640g.
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
Both the Sigma 120-400mm F4.5-5.6 DG OS HSM and the Nikon 80-400mm f4.5-5.6D ED VR have the same Filter thread size of 77mm.
Below are links to the 77mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sigma 120-400mm F4.5-5.6 DG OS HSM and the Nikon 80-400mm f4.5-5.6D ED VR 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 120-400mm F4.5-5.6 DG OS HSM is also available in Canon EF and Sigma SA mounts.
Focal Range
Sigma 120-400mm F4.5-5.6 DG OS HSM has a focal range of 120-400mm and
3.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
180 - 600mm.
On the other hand, the Nikon 80-400mm f4.5-5.6D ED VR has a focal range of 80-400mm and 5.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 120 - 600mm.