The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 28-200mm F2.8-5.6 Di III 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 28-200mm F2.8-5.6 Di III is the longer of the two lenses at 117mm. The Sigma 18-200mm F3.5-6.3 DC with a length of 78mm, is 39mm shorter. Besides being longer, the Tamron 28-200mm F2.8-5.6 Di III 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, 29% (171g) lighter than the Tamron 28-200mm F2.8-5.6 Di III's weight of 576g.
Filter Threads
The Tamron 28-200mm F2.8-5.6 Di III has a filter size of 67mm whereas the Sigma 18-200mm F3.5-6.3 DC has a 62mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Tamron 28-200mm F2.8-5.6 Di III:
And these are the 62mm filters that we recommend for the Sigma 18-200mm F3.5-6.3 DC:
Lens Mounts
The Tamron 28-200mm F2.8-5.6 Di III has the Sony E lens mount whereas the Sigma 18-200mm F3.5-6.3 DC has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount.
Sigma 18-200mm F3.5-6.3 DC is also available in Nikon F (DX) , Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Tamron 28-200mm F2.8-5.6 Di III has a focal range of 28-200mm and
7.1X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
42 - 300mm.
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 28.8-320mm when used on a APS-C / DX format camera.
