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 100-400mm F5-6.3 OS 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 18-300mm F3.5-6.3 Di with a length of 126mm, is 71mm shorter. Besides being longer, the Sigma 100-400mm F5-6.3 OS also has a larger diameter of 86mm compared to the Tamron 18-300mm F3.5-6.3 Di's 76mm diameter.
Below you can find a scaled side-by-side image of Tamron 18-300mm F3.5-6.3 Di and Sigma 100-400mm F5-6.3 OS to get a better idea of how their sizes compare in real life.
Comparison image of the Tamron 18-300mm F3.5-6.3 Di and the Sigma 100-400mm F5-6.3 OS 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 18-300mm F3.5-6.3 Di weighs 620g, which means it is 515g (45%) lighter than the Sigma 100-400mm F5-6.3 OS which has a weight of 1135g.
Filter Threads
Both the Tamron 18-300mm F3.5-6.3 Di and the Sigma 100-400mm F5-6.3 OS 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 Tamron 18-300mm F3.5-6.3 Di and the Sigma 100-400mm F5-6.3 OS 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 .
Tamron 18-300mm F3.5-6.3 Di is also available in the Fujifilm X mount.
Sigma 100-400mm F5-6.3 OS is also available in Leica L and Fujifilm X 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 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 .