The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-250mm F3.5-6.3 DC OS HSM and the Tamron AF 18-270mm f3.5-6.3 II VC LD 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. Tamron AF 18-270mm f3.5-6.3 II VC LD is the longer of the two lenses at 101mm. The Sigma 18-250mm F3.5-6.3 DC OS HSM with a length of 89mm, is 12mm shorter. Besides being longer, the Tamron AF 18-270mm f3.5-6.3 II VC LD also has a larger diameter of 80mm compared to the Sigma 18-250mm F3.5-6.3 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 18-250mm F3.5-6.3 DC OS HSM weighs 470g, which means it is 90g (16%) lighter than the Tamron AF 18-270mm f3.5-6.3 II VC LD which has a weight of 560g.
Below you can find the dimension and weight table of the SuperZoom Lenses in Nikon F (DX) Mount for size comparison purposes.
Super Telephoto Lenses in Nikon F (DX) Mount for Size Comparison
Filter Threads
Both the Sigma 18-250mm F3.5-6.3 DC OS HSM and the Tamron AF 18-270mm f3.5-6.3 II VC LD have the same Filter thread size of 72mm.
Below are links to the 72mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sigma 18-250mm F3.5-6.3 DC OS HSM and the Tamron AF 18-270mm f3.5-6.3 II VC LD 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 18-250mm F3.5-6.3 DC OS HSM is also available in Canon EF , Pentax KAF3, Sony Alpha, Sigma SA, Canon EF, Nikon F (DX), Pentax KAF3, Sony Alpha and Sigma SA mounts.
Tamron AF 18-270mm f3.5-6.3 II VC LD is also available in Canon EF mount.
Focal Range
Sigma 18-250mm F3.5-6.3 DC OS HSM has a focal range of 18-250mm and
13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-375mm when used on a APS-C / DX format camera.
On the other hand, the Tamron AF 18-270mm f3.5-6.3 II VC LD has a focal range of 18-270mm and 15.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-405mm when used on a APS-C / DX format camera.