The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-300 F3.5-6.3 DC OS HSM and the Tamron 16-300mm f3.5-6.3 II VC PZD for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sigma 18-300 F3.5-6.3 DC OS HSM is the longer of the two lenses at 102mm. The Tamron 16-300mm f3.5-6.3 II VC PZD with a length of 100mm is 2mm shorter. Besides being longer, the Sigma 18-300 F3.5-6.3 DC OS HSM also has a larger diameter of 79mm compared to Tamron 16-300mm f3.5-6.3 II VC PZD's 75mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Tamron 16-300mm f3.5-6.3 II VC PZD weighs 540g, 7% (45g) lighter than the Sigma 18-300 F3.5-6.3 DC OS HSM's weight of 585g.
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
Lens Mounts
Both Sigma 18-300 F3.5-6.3 DC OS HSM and Tamron 16-300mm f3.5-6.3 II VC PZD 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 18-300 F3.5-6.3 DC OS HSM is also available in Canon EF , Pentax KAF3, Sigma SA and Sony Alpha mounts.
Tamron 16-300mm f3.5-6.3 II VC PZD is also available in Canon EF and Sony Alpha mounts.
Focal Range
Sigma 18-300 F3.5-6.3 DC OS HSM 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. Tamron 16-300mm f3.5-6.3 II VC PZD has a focal range of 16-300mm and 18.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 24-450mm when used on a APS-C / DX format camera.