The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 100-400mm F5-6.3 OS 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. Sigma 100-400mm F5-6.3 OS is the longer of the two lenses at 197mm. The Tamron 17-70 F2.8 Di III-A VC with a length of 119mm, is 78mm shorter. Besides being longer, the Sigma 100-400mm F5-6.3 OS also has a larger diameter of 86mm compared to the Tamron 17-70 F2.8 Di III-A VC's 75mm diameter.
Below you can find a scaled side-by-side image of Sigma 100-400mm F5-6.3 OS 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 100-400mm F5-6.3 OS 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. Tamron 17-70 F2.8 Di III-A VC weighs 525g, 53% (610g) lighter than the Sigma 100-400mm F5-6.3 OS's weight of 1135g.
Filter Threads
Both the Sigma 100-400mm F5-6.3 OS and the Tamron 17-70 F2.8 Di III-A VC have the same Filter thread size of 67mm .
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sigma 100-400mm F5-6.3 OS and the Tamron 17-70 F2.8 Di III-A VC has the same Fujifilm X lens mount . Some of the latest released cameras that are compatible with the Fujifilm X lenses are Fujifilm X-T30 III , Fujifilm X-E5 and Fujifilm X-M5 .
Leica L and Sony E mounts.
Sony E mount.
Focal Range
Sigma 100-400mm F5-6.3 OS has a focal range of 100-400mm and
4.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
150 - 600mm .
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.
