The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 18-270mm f3.5-6.3 II VC PZD and the Sigma 18-200mm F3.5-6.3 DC 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 18-270mm f3.5-6.3 II VC PZD is the longer of the two lenses at 88mm. The Sigma 18-200mm F3.5-6.3 DC with a length of 78mm, is 10mm shorter. Besides being longer, the Tamron 18-270mm f3.5-6.3 II VC PZD also has a larger diameter of 74mm compared to the Sigma 18-200mm F3.5-6.3 DC's 70mm 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 18-200mm F3.5-6.3 DC weighs 405g, 9% (45g) lighter than the Tamron 18-270mm f3.5-6.3 II VC PZD's weight of 450g.
Filter Threads
Both the Tamron 18-270mm f3.5-6.3 II VC PZD and the Sigma 18-200mm F3.5-6.3 DC have the same Filter thread size of 62mm.
Below are links to the 62mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Tamron 18-270mm f3.5-6.3 II VC PZD has the Nikon F (DX) lens mount whereas the Sigma 18-200mm F3.5-6.3 DC has the Sigma SA lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount and Sigma SD1 Merrill, Sigma SD1 and for the Sigma SA Mount.
Tamron 18-270mm f3.5-6.3 II VC PZD is also available in Canon EF mount.
Sigma 18-200mm F3.5-6.3 DC is also available in Canon EF , Nikon F (DX), Pentax KAF and Sony Alpha mounts.
Focal Range
Tamron 18-270mm f3.5-6.3 II VC PZD 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.
On the other hand, the Sigma 18-200mm F3.5-6.3 DC has a focal range of 18-200mm and 11.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-300mm when used on a APS-C / DX format camera.