The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-125mm F3.8-5.6 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 18-125mm F3.8-5.6 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 18-125mm F3.8-5.6 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.
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 18-125mm F3.8-5.6 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 18-125mm F3.8-5.6 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 18-125mm F3.8-5.6 DC OS HSM is also available in the Canon EF and Sigma SA mounts.
Focal Range
Sigma 18-125mm F3.8-5.6 DC OS HSM has a focal range of 18-125mm and
6.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-187.5mm 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.
