The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-50mm F2.8-4.5 DC OS HSM and the Nikon 18-140mm 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. Nikon 18-140mm f3.5-5.6G ED VR is the longer of the two lenses at 97mm. The Sigma 18-50mm F2.8-4.5 DC OS HSM with a length of 89mm, is 8mm shorter. Besides being longer, the Nikon 18-140mm f3.5-5.6G ED VR also has a larger diameter of 78mm compared to the Sigma 18-50mm F2.8-4.5 DC OS HSM's 74mm 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. Sigma 18-50mm F2.8-4.5 DC OS HSM weighs 395g, which means it is 95g (19%) lighter than the Nikon 18-140mm f3.5-5.6G ED VR which has a weight of 490g.
Below you can find the dimension and weight table of the SuperZoom Lenses in Nikon F (DX) Mount for size comparison purposes.
Superzoom Lenses in Nikon F (DX) Mount for Size Comparison
Filter Threads
Both the Sigma 18-50mm F2.8-4.5 DC OS HSM and the Nikon 18-140mm f3.5-5.6G ED VR have the same Filter thread size of 67mm.
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sigma 18-50mm F2.8-4.5 DC OS HSM and the Nikon 18-140mm f3.5-5.6G ED VR has the same Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (DX) lenses are Nikon D3500, Nikon D7500 and Nikon D5600.
Sigma 18-50mm F2.8-4.5 DC OS HSM is also available in the Canon EF , Pentax KAF3, Sony Alpha and Sigma SA mounts.
Focal Range
Sigma 18-50mm F2.8-4.5 DC OS HSM has a focal range of 18-50mm and
2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-75mm when used on a APS-C / DX format camera.
On the other hand, the Nikon 18-140mm f3.5-5.6G ED VR has a focal range of 18-140mm and 7.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-210mm when used on a APS-C / DX format camera.
