The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 100-400mm F4.5-5.6 and the Sigma 70-300mm F4-5.6 DG 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. Sony FE 100-400mm F4.5-5.6 is the longer of the two lenses at 205mm. The Sigma 70-300mm F4-5.6 DG OS with a length of 126mm, is 79mm shorter. Besides being longer, the Sony FE 100-400mm F4.5-5.6 also has a larger diameter of 94mm compared to the Sigma 70-300mm F4-5.6 DG OS's 77mm 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 70-300mm F4-5.6 DG OS weighs 610g, 56% (785g) lighter than the Sony FE 100-400mm F4.5-5.6's weight of 1395g.
Filter Threads
The Sony FE 100-400mm F4.5-5.6 has a filter size of 77mm whereas the Sigma 70-300mm F4-5.6 DG OS has a 58mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Sony FE 100-400mm F4.5-5.6:
And these are the 58mm filters that we recommend for the Sigma 70-300mm F4-5.6 DG OS:
Lens Mounts
The Sony FE 100-400mm F4.5-5.6 has the Sony E lens mount whereas the Sigma 70-300mm F4-5.6 DG OS has the Sony Alpha lens mount. Some of the latest released cameras that are compatible with these mounts are Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount and Sony A99 II, Sony A68 and Sony A77 II for the Sony Alpha Mount.
Sigma 70-300mm F4-5.6 DG OS is also available in Canon EF , Nikon F (FX), Pentax KAF3 and Sigma SA mounts.
Focal Range
Sony FE 100-400mm F4.5-5.6 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 Sigma 70-300mm F4-5.6 DG OS has a focal range of 70-300mm and 4.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 105 - 450mm.