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 18-200mm F3.5-6.3 DC OS HSM C for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Sigma 18-200mm F3.5-6.3 DC OS HSM C is the longer of the two lenses at 86mm. The Tamron AF 18-200mm f3.5-6.3 XR II LD with a length of 84mm, is 2mm shorter. On the other hand, the Tamron AF 18-200mm f3.5-6.3 XR II LD has a larger diameter of 74mm compared to the Sigma 18-200mm F3.5-6.3 DC OS HSM C's 71mm diameter.
The 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 AF 18-200mm f3.5-6.3 XR II LD weighs 398g, which means it is 32g (7%) lighter than the Sigma 18-200mm F3.5-6.3 DC OS HSM C which has a weight of 430g.
Below you can find the dimension and weight table of the SuperZoom Lenses in Sony Alpha Mount for size comparison purposes.
SuperZoom Lenses in Sony Alpha Mount for Size Comparison
Lens Mounts
Both the Tamron AF 18-200mm f3.5-6.3 XR II LD and the Sigma 18-200mm F3.5-6.3 DC OS HSM C has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A68, Sony A77 II and Sony A58.
Tamron AF 18-200mm f3.5-6.3 XR II LD is also available in Canon EF , Nikon F (DX) and Pentax KAF mounts.
Sigma 18-200mm F3.5-6.3 DC OS HSM C is also available in Canon EF , Nikon F (DX), Pentax KAF3 and Sigma SA mounts.
Focal Range
Both lenses have the same focal range of 18-200mm and the fastest aperture of F3.5 - F6.3.