The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 17-70 F2.8 Di III-A VC 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. Tamron 17-70 F2.8 Di III-A VC is the longer of the two lenses at 119mm. The Sigma 50-200mm F4-5.6 DC OS HSM with a length of 102mm, is 17mm shorter. Besides being longer, the Tamron 17-70 F2.8 Di III-A VC also has a larger diameter of 75mm compared to the Sigma 50-200mm F4-5.6 DC OS HSM's 74mm 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 50-200mm F4-5.6 DC OS HSM weighs 420g, 19% (105g) lighter than the Tamron 17-70 F2.8 Di III-A VC's weight of 525g.
Filter Threads
The Tamron 17-70 F2.8 Di III-A VC 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 17-70 F2.8 Di III-A VC:
And these are the 55mm filters that we recommend for the Sigma 50-200mm F4-5.6 DC OS HSM:
Lens Mounts
The Tamron 17-70 F2.8 Di III-A VC 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 ZV-E10 II, Sony A6700 and Sony FX30 for the Sony E Mount and Sony A68, Sony A77 II and Sony A58 for the Sony Alpha Mount.
Tamron 17-70 F2.8 Di III-A VC is also available in the Fujifilm X 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 17-70 F2.8 Di III-A VC has a focal range of 17-70mm and
4.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
25.5-105mm when used on a APS-C / DX format camera.
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.
