The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 18-400mm F3.5-6.3 VC and the Sigma 100-400mm F5-6.3 DG 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. Sigma 100-400mm F5-6.3 DG OS HSM is the longer of the two lenses at 182mm. The Tamron 18-400mm F3.5-6.3 VC with a length of 124mm, is 58mm shorter. Besides being longer, the Sigma 100-400mm F5-6.3 DG OS HSM also has a larger diameter of 86mm compared to the Tamron 18-400mm F3.5-6.3 VC's 79mm 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. Tamron 18-400mm F3.5-6.3 VC weighs 710g, which means it is 450g (38%) lighter than the Sigma 100-400mm F5-6.3 DG OS HSM which has a weight of 1160g.
Filter Threads
The Tamron 18-400mm F3.5-6.3 VC has a filter size of 72mm whereas the Sigma 100-400mm F5-6.3 DG OS HSM 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 72mm filters that we recommend you to consider for the Tamron 18-400mm F3.5-6.3 VC:
And these are the 67mm filters that we recommend for the Sigma 100-400mm F5-6.3 DG OS HSM:
Lens Mounts
The Tamron 18-400mm F3.5-6.3 VC has the Nikon F (DX) lens mount whereas the Sigma 100-400mm F5-6.3 DG OS HSM has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount and Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Tamron 18-400mm F3.5-6.3 VC is also available in the Canon EF-S mount.
Sigma 100-400mm F5-6.3 DG OS HSM is also available in Sigma SA and Nikon F (FX) mounts.
Focal Range
Tamron 18-400mm F3.5-6.3 VC has a focal range of 18-400mm and
22.2X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-600mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 100-400mm F5-6.3 DG OS HSM has a focal range of 100-400mm and 4.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 160 - 640mm.
