The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-50mm F2.8 DC DN C and the Tamron 17-70 F2.8 Di III-A VC 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 18-50mm F2.8 DC DN C with a length of 75mm, is 44mm 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 18-50mm F2.8 DC DN C's 65mm diameter.
Below you can find a scaled side-by-side image of Sigma 18-50mm F2.8 DC DN C and Tamron 17-70 F2.8 Di III-A VC to get a better idea of how their sizes compare in real life.
Comparison image of the Sigma 18-50mm F2.8 DC DN C and the Tamron 17-70 F2.8 Di III-A VC Size and Weight 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 18-50mm F2.8 DC DN C weighs 290g, which means it is 235g (44%) lighter than the Tamron 17-70 F2.8 Di III-A VC which has a weight of 525g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Sony E Mount for size comparison purposes.
Standard Sony E Mount
Filter Threads
The Sigma 18-50mm F2.8 DC DN C has a filter size of 55mm whereas the Tamron 17-70 F2.8 Di III-A VC has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 55mm filters that we recommend you to consider for the Sigma 18-50mm F2.8 DC DN C:
And these are the 67mm filters that we recommend for the Tamron 17-70 F2.8 Di III-A VC:
Lens Mounts
Both the Sigma 18-50mm F2.8 DC DN C and the Tamron 17-70 F2.8 Di III-A VC has the same Sony E lens mount . Some of the latest released cameras that are compatible with the Sony E lenses are Sony ZV-E10 II , Sony A6700 and Sony FX30 .
Leica L and Fujifilm X mounts.
Fujifilm X mount.
Focal Range
Sigma 18-50mm F2.8 DC DN C has a focal range of 18-50mm and
2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-75mm when used on a APS-C / DX format camera.
On the other hand, the 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.
