The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron AF 18-250mm f3.5-6.3 II LD 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 AF 18-250mm f3.5-6.3 II LD is the longer of the two lenses at 84mm. The Sigma 18-200mm F3.5-6.3 DC with a length of 78mm, is 6mm shorter. Besides being longer, the Tamron AF 18-250mm f3.5-6.3 II LD 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, 5% (25g) lighter than the Tamron AF 18-250mm f3.5-6.3 II LD's weight of 430g.
Filter Threads
Both the Tamron AF 18-250mm f3.5-6.3 II LD 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 AF 18-250mm f3.5-6.3 II LD has the Canon EF lens mount whereas the Sigma 18-200mm F3.5-6.3 DC has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Tamron AF 18-250mm f3.5-6.3 II LD is also available in the Nikon F (DX) , Sony Alpha and Pentax KAF mounts.
Sigma 18-200mm F3.5-6.3 DC is also available in Canon EF , Nikon F (DX), Sony Alpha and Sigma SA mounts.
Focal Range
Tamron AF 18-250mm f3.5-6.3 II LD has a focal range of 18-250mm and
13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
28.8-400mm 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.
