The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 20-40mm F2.8 VXD and the Sigma 50-200mm F4-5.6 DC OS 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 50-200mm F4-5.6 DC OS HSM is the longer of the two lenses at 102mm. The Tamron 20-40mm F2.8 VXD with a length of 86mm, is 16mm 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 20-40mm F2.8 VXD weighs 365g, which means it is 55g (13%) lighter than the Sigma 50-200mm F4-5.6 DC OS HSM which has a weight of 420g.
Filter Threads
The Tamron 20-40mm F2.8 VXD has a filter size of 67mm whereas the Sigma 50-200mm F4-5.6 DC OS HSM has a 55mm 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 20-40mm F2.8 VXD:
And these are the 55mm filters that we recommend for the Sigma 50-200mm F4-5.6 DC OS HSM:
Lens Mounts
The Tamron 20-40mm F2.8 VXD has the Sony E lens mount whereas the Sigma 50-200mm F4-5.6 DC OS HSM has the Sony Alpha 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 Sony A68, Sony A77 II and Sony A58 for the Sony Alpha Mount.
Sigma 50-200mm F4-5.6 DC OS HSM is also available in Canon EF , Pentax KAF3, Sigma SA and Nikon F (DX) mounts.
Focal Range
Tamron 20-40mm F2.8 VXD has a focal range of 20-40mm and
2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
30 - 60mm.
On the other hand, the Sigma 50-200mm F4-5.6 DC OS HSM has a focal range of 50-200mm and 4.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 75-300mm when used on a APS-C / DX format camera.
