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 17-70mm F2.8-4 DC OS HSM C 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 17-70mm F2.8-4 DC OS HSM C with a length of 82mm, is 37mm shorter. On the other hand, the Sigma 17-70mm F2.8-4 DC OS HSM C has a larger diameter of 79mm compared to the Tamron 17-70 F2.8 Di III-A VC's 75mm 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 17-70mm F2.8-4 DC OS HSM C weighs 465g, 11% (60g) 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 17-70mm F2.8-4 DC OS HSM C has a 72mm 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 72mm filters that we recommend for the Sigma 17-70mm F2.8-4 DC OS HSM C:
Lens Mounts
The Tamron 17-70 F2.8 Di III-A VC has the Fujifilm X lens mount whereas the Sigma 17-70mm F2.8-4 DC OS HSM C has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5 for the Fujifilm X Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount.
Tamron 17-70 F2.8 Di III-A VC is also available in the Sony E mount.
Sigma 17-70mm F2.8-4 DC OS HSM C is also available in Pentax KAF3 , Sony Alpha, Sigma SA and Nikon F (DX) mounts.
Focal Range
Both lenses have the same focal range of
17-70mm but while Tamron 17-70 F2.8 Di III-A VC has the fastest aperture of
F2.8, the Sigma 17-70mm F2.8-4 DC OS HSM C's widest aperture value is
F2.8 - F4.0.
