The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 70-200mm F2.8 EX DG OS HSM and the Nikon 18-300mm F3.5-5.6G 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 70-200mm F2.8 EX DG OS HSM is the longer of the two lenses at 197mm. The Nikon 18-300mm F3.5-5.6G ED VR with a length of 120mm, is 77mm shorter. Besides being longer, the Sigma 70-200mm F2.8 EX DG OS HSM also has a larger diameter of 86mm compared to the Nikon 18-300mm F3.5-5.6G ED VR's 83mm 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 18-300mm F3.5-5.6G ED VR weighs 830g, 41% (600g) lighter than the Sigma 70-200mm F2.8 EX DG OS HSM's weight of 1430g.
Filter Threads
Both the Sigma 70-200mm F2.8 EX DG OS HSM and the Nikon 18-300mm F3.5-5.6G 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
The Sigma 70-200mm F2.8 EX DG OS HSM has the Nikon F (FX) lens mount whereas the Nikon 18-300mm F3.5-5.6G ED VR has the Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount and Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount.
Sigma 70-200mm F2.8 EX DG OS HSM is also available in Canon EF , Pentax KAF3, Sony Alpha and Sigma SA mounts.
Focal Range
Sigma 70-200mm F2.8 EX DG OS HSM 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.
On the other hand, the Nikon 18-300mm F3.5-5.6G ED VR has a focal range of 18-300mm and 16.7X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-450mm when used on a APS-C / DX format camera.