The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 18-300mm F3.5-6.3 Di 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 18-300mm F3.5-6.3 Di is the longer of the two lenses at 126mm. The Sigma 17-70mm F2.8-4 DC OS HSM C with a length of 82mm, is 44mm 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 18-300mm F3.5-6.3 Di's 76mm 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, 25% (155g) lighter than the Tamron 18-300mm F3.5-6.3 Di's weight of 620g.
Filter Threads
The Tamron 18-300mm F3.5-6.3 Di 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 18-300mm F3.5-6.3 Di:
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 18-300mm F3.5-6.3 Di has the Sony E lens mount whereas the Sigma 17-70mm F2.8-4 DC OS HSM C has the Nikon F (DX) 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 Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount.
Tamron 18-300mm F3.5-6.3 Di is also available in the Fujifilm X mount.
Sigma 17-70mm F2.8-4 DC OS HSM C is also available in Canon EF , Pentax KAF3, Sony Alpha and Sigma SA mounts.
Focal Range
Tamron 18-300mm F3.5-6.3 Di has a focal range of 18-300mm and
16.7X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-450mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 17-70mm F2.8-4 DC OS HSM C 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.
