The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron AF 18-200mm f3.5-6.3 XR II LD and the Sigma 18-125mm F3.8-5.6 DC HSM 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. Sigma 18-125mm F3.8-5.6 DC HSM is the longer of the two lenses at 89mm. The Tamron AF 18-200mm f3.5-6.3 XR II LD with a length of 84mm, is 5mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 74mm.
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. Tamron AF 18-200mm f3.5-6.3 XR II LD weighs 398g, which means it is 92g (18%) lighter than the Sigma 18-125mm F3.8-5.6 DC HSM which has a weight of 490g.
Filter Threads
Both the Tamron AF 18-200mm f3.5-6.3 XR II LD and the Sigma 18-125mm F3.8-5.6 DC HSM 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 AF 18-200mm f3.5-6.3 XR II LD has the Sony Alpha lens mount whereas the Sigma 18-125mm F3.8-5.6 DC HSM has the Pentax KAF3 lens mount. Some of the latest released cameras that are compatible with these mounts are Sony A68, Sony A77 II and Sony A58 for the Sony Alpha Mount and , and for the Pentax KAF3 Mount.
Tamron AF 18-200mm f3.5-6.3 XR II LD is also available in the Canon EF , Nikon F (DX) and Pentax KAF mounts.
Sigma 18-125mm F3.8-5.6 DC HSM is also available in Sony Alpha mount.
Focal Range
Tamron AF 18-200mm f3.5-6.3 XR II LD 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.
On the other hand, the Sigma 18-125mm F3.8-5.6 DC 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.
